21551616452 has 12 divisors (see below), whose sum is σ = 39015857580. Its totient is φ = 10404228576.

The previous prime is 21551616413. The next prime is 21551616473. The reversal of 21551616452 is 25461615512.

It can be written as a sum of positive squares in 2 ways, for example, as 9795852676 + 11755763776 = 98974^2 + 108424^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 92894783 + ... + 92895014.

It is an arithmetic number, because the mean of its divisors is an integer number (3251321465).

Almost surely, 2^21551616452 is an apocalyptic number.

It is an amenable number.

21551616452 is a deficient number, since it is larger than the sum of its proper divisors (17464241128).

21551616452 is a wasteful number, since it uses less digits than its factorization.

21551616452 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 185789830 (or 185789828 counting only the distinct ones).

The product of its digits is 72000, while the sum is 38.

The spelling of 21551616452 in words is "twenty-one billion, five hundred fifty-one million, six hundred sixteen thousand, four hundred fifty-two".