2101021 has 8 divisors (see below), whose sum is σ = 2341080. Its totient is φ = 1872192.

The previous prime is 2101019. The next prime is 2101051. The reversal of 2101021 is 1201012.

It can be written as a sum of positive squares in 4 ways, for example, as 12996 + 2088025 = 114^2 + 1445^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 2101021 - 2¹ = 2101019 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2100995 and 2101013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2101051) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2410 + ... + 3163.

It is an arithmetic number, because the mean of its divisors is an integer number (292635).

2^2101021 is an apocalyptic number.

It is an amenable number.

2101021 is a deficient number, since it is larger than the sum of its proper divisors (240059).

2101021 is a wasteful number, since it uses less digits than its factorization.

2101021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5615.

The product of its (nonzero) digits is 4, while the sum is 7.

The square root of 2101021 is about 1449.4899102788. The cubic root of 2101021 is about 128.0786666494.

Adding to 2101021 its reverse (1201012), we get a palindrome (3302033).

Subtracting from 2101021 its reverse (1201012), we obtain a palindrome (900009).

The spelling of 2101021 in words is "two million, one hundred one thousand, twenty-one".