21002653213 has 4 divisors (see below), whose sum is σ = 22238103420. Its totient is φ = 19767203008.

The previous prime is 21002653193. The next prime is 21002653283. The reversal of 21002653213 is 31235620012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 12663676089 + 8338977124 = 112533^2 + 91318^2 .

It is a cyclic number.

It is not a de Polignac number, because 21002653213 - 2⁹ = 21002652701 is a prime.

It is a super-2 number, since 2×21002653213² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21002653283) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 617725078 + ... + 617725111.

It is an arithmetic number, because the mean of its divisors is an integer number (5559525855).

Almost surely, 2^21002653213 is an apocalyptic number.

It is an amenable number.

21002653213 is a deficient number, since it is larger than the sum of its proper divisors (1235450207).

21002653213 is a wasteful number, since it uses less digits than its factorization.

21002653213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1235450206.

The product of its (nonzero) digits is 2160, while the sum is 25.

The spelling of 21002653213 in words is "twenty-one billion, two million, six hundred fifty-three thousand, two hundred thirteen".