21250020875 has 16 divisors (see below), whose sum is σ = 26524985760. Its totient is φ = 16996837600.

The previous prime is 21250020871. The next prime is 21250020881. The reversal of 21250020875 is 57802005212.

It is a happy number.

It is not a de Polignac number, because 21250020875 - 2² = 21250020871 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21250020871) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 837881 + ... + 862869.

It is an arithmetic number, because the mean of its divisors is an integer number (1657811610).

Almost surely, 2^21250020875 is an apocalyptic number.

21250020875 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21250020875 is a deficient number, since it is larger than the sum of its proper divisors (5274964885).

21250020875 is an equidigital number, since it uses as much as digits as its factorization.

21250020875 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31807 (or 31797 counting only the distinct ones).

The product of its (nonzero) digits is 11200, while the sum is 32.

The spelling of 21250020875 in words is "twenty-one billion, two hundred fifty million, twenty thousand, eight hundred seventy-five".