220021001 has 4 divisors (see below), whose sum is σ = 220052352. Its totient is φ = 219989652.

The previous prime is 220020949. The next prime is 220021003. The reversal of 220021001 is 100120022.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 220021001 - 2²² = 215826697 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 220021001.

It is not an unprimeable number, because it can be changed into a prime (220021003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 236 + ... + 20978.

It is an arithmetic number, because the mean of its divisors is an integer number (55013088).

Almost surely, 2^220021001 is an apocalyptic number.

It is an amenable number.

220021001 is a deficient number, since it is larger than the sum of its proper divisors (31351).

220021001 is a wasteful number, since it uses less digits than its factorization.

220021001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31350.

The product of its (nonzero) digits is 8, while the sum is 8.

The square root of 220021001 is about 14833.1049008628. The cubic root of 220021001 is about 603.7002820174.

Adding to 220021001 its reverse (100120022), we get a palindrome (320141023).

The spelling of 220021001 in words is "two hundred twenty million, twenty-one thousand, one".