13870021 has 4 divisors (see below), whose sum is σ = 15130944. Its totient is φ = 12609100.

The previous prime is 13869991. The next prime is 13870039. The reversal of 13870021 is 12007831.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 13870021 - 2¹³ = 13861829 is a prime.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 13869974 and 13870001.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13870061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 630445 + ... + 630466.

It is an arithmetic number, because the mean of its divisors is an integer number (3782736).

Almost surely, 2^13870021 is an apocalyptic number.

13870021 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

13870021 is a deficient number, since it is larger than the sum of its proper divisors (1260923).

13870021 is a wasteful number, since it uses less digits than its factorization.

13870021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1260922.

The product of its (nonzero) digits is 336, while the sum is 22.

The square root of 13870021 is about 3724.2477092696. The cubic root of 13870021 is about 240.2660302388.

Adding to 13870021 its reverse (12007831), we get a palindrome (25877852).

The spelling of 13870021 in words is "thirteen million, eight hundred seventy thousand, twenty-one".