21252885709 has 4 divisors (see below), whose sum is σ = 23184966240. Its totient is φ = 19320805180.

The previous prime is 21252885691. The next prime is 21252885721. The reversal of 21252885709 is 90758825212.

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 21252885709 - 2⁵ = 21252885677 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21252285709) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 966040249 + ... + 966040270.

It is an arithmetic number, because the mean of its divisors is an integer number (5796241560).

Almost surely, 2^21252885709 is an apocalyptic number.

It is an amenable number.

21252885709 is a deficient number, since it is larger than the sum of its proper divisors (1932080531).

21252885709 is a wasteful number, since it uses less digits than its factorization.

21252885709 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1932080530.

The product of its (nonzero) digits is 806400, while the sum is 49.

The spelling of 21252885709 in words is "twenty-one billion, two hundred fifty-two million, eight hundred eighty-five thousand, seven hundred nine".