21609177952 has 24 divisors (see below), whose sum is σ = 42572930400. Its totient is φ = 10797005184.

The previous prime is 21609177929. The next prime is 21609177973. The reversal of 21609177952 is 25977190612.

It is a happy number.

It is a super-2 number, since 2×21609177952² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21609177896 and 21609177905.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 190552 + ... + 282007.

It is an arithmetic number, because the mean of its divisors is an integer number (1773872100).

Almost surely, 2^21609177952 is an apocalyptic number.

It is an amenable number.

21609177952 is a deficient number, since it is larger than the sum of its proper divisors (20963752448).

21609177952 is a wasteful number, since it uses less digits than its factorization.

21609177952 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 473998 (or 473990 counting only the distinct ones).

The product of its (nonzero) digits is 476280, while the sum is 49.

The spelling of 21609177952 in words is "twenty-one billion, six hundred nine million, one hundred seventy-seven thousand, nine hundred fifty-two".