21052197090 has 24 divisors (see below), whose sum is σ = 54735712668. Its totient is φ = 5613919200.

The previous prime is 21052197079. The next prime is 21052197109. The reversal of 21052197090 is 9079125012.

It can be written as a sum of positive squares in 2 ways, for example, as 19076305689 + 1975891401 = 138117^2 + 44451^2 .

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 116956561 + ... + 116956740.

Almost surely, 2^21052197090 is an apocalyptic number.

21052197090 is an abundant number, since it is smaller than the sum of its proper divisors (33683515578).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21052197090 is a wasteful number, since it uses less digits than its factorization.

21052197090 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 233913314 (or 233913311 counting only the distinct ones).

The product of its (nonzero) digits is 11340, while the sum is 36.

The spelling of 21052197090 in words is "twenty-one billion, fifty-two million, one hundred ninety-seven thousand, ninety".