21005168552 has 16 divisors (see below), whose sum is σ = 39478247700. Its totient is φ = 10477635840.

The previous prime is 21005168551. The next prime is 21005168603. The reversal of 21005168552 is 25586150012.

It can be written as a sum of positive squares in 2 ways, for example, as 21003545476 + 1623076 = 144926^2 + 1274^2 .

It is not an unprimeable number, because it can be changed into a prime (21005168551) 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, 3114977 + ... + 3121712.

Almost surely, 2^21005168552 is an apocalyptic number.

It is an amenable number.

21005168552 is a deficient number, since it is larger than the sum of its proper divisors (18473079148).

21005168552 is a wasteful number, since it uses less digits than its factorization.

21005168552 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6237116 (or 6237112 counting only the distinct ones).

The product of its (nonzero) digits is 24000, while the sum is 35.

The spelling of 21005168552 in words is "twenty-one billion, five million, one hundred sixty-eight thousand, five hundred fifty-two".