21369561512 has 16 divisors (see below), whose sum is σ = 43150076340. Its totient is φ = 9862874496.

The previous prime is 21369561491. The next prime is 21369561539. The reversal of 21369561512 is 21516596312.

It can be written as a sum of positive squares in 2 ways, for example, as 21296732356 + 72829156 = 145934^2 + 8534^2 .

It is a super-2 number, since 2×21369561512² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21369561512.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 102738173 + ... + 102738380.

Almost surely, 2^21369561512 is an apocalyptic number.

It is an amenable number.

21369561512 is an abundant number, since it is smaller than the sum of its proper divisors (21780514828).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21369561512 is a wasteful number, since it uses less digits than its factorization.

21369561512 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 205476572 (or 205476568 counting only the distinct ones).

The product of its digits is 97200, while the sum is 41.

The spelling of 21369561512 in words is "twenty-one billion, three hundred sixty-nine million, five hundred sixty-one thousand, five hundred twelve".