21252885705 has 24 divisors (see below), whose sum is σ = 38202720192. Its totient is φ = 11334871728.

The previous prime is 21252885691. The next prime is 21252885721. The reversal of 21252885705 is 50758825212.

21252885705 is a `hidden beast` number, since 21 + 2 + 52 + 8 + 8 + 570 + 5 = 666.

It is not a de Polignac number, because 21252885705 - 2⁵ = 21252885673 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

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 23 ways as a sum of consecutive naturals, for example, 8744829 + ... + 8747258.

It is an arithmetic number, because the mean of its divisors is an integer number (1591780008).

Almost surely, 2^21252885705 is an apocalyptic number.

It is an amenable number.

21252885705 is a deficient number, since it is larger than the sum of its proper divisors (16949834487).

21252885705 is an equidigital number, since it uses as much as digits as its factorization.

21252885705 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17492107 (or 17492095 counting only the distinct ones).

The product of its (nonzero) digits is 448000, while the sum is 45.

The spelling of 21252885705 in words is "twenty-one billion, two hundred fifty-two million, eight hundred eighty-five thousand, seven hundred five".