21550136625 has 48 divisors (see below), whose sum is σ = 39897728208. Its totient is φ = 11182752000.

The previous prime is 21550136617. The next prime is 21550136651. The reversal of 21550136625 is 52663105512.

21550136625 is a `hidden beast` number, since 2 + 15 + 5 + 0 + 13 + 6 + 625 = 666.

It can be written as a sum of positive squares in 8 ways, for example, as 5728521969 + 15821614656 = 75687^2 + 125784^2 .

It is not a de Polignac number, because 21550136625 - 2³ = 21550136617 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21550136625.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 217236 + ... + 300485.

It is an arithmetic number, because the mean of its divisors is an integer number (831202671).

Almost surely, 2^21550136625 is an apocalyptic number.

21550136625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21550136625 is a deficient number, since it is larger than the sum of its proper divisors (18347591583).

21550136625 is a wasteful number, since it uses less digits than its factorization.

21550136625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 517779 (or 517766 counting only the distinct ones).

The product of its (nonzero) digits is 54000, while the sum is 36.

The spelling of 21550136625 in words is "twenty-one billion, five hundred fifty million, one hundred thirty-six thousand, six hundred twenty-five".