21136555452 has 12 divisors (see below), whose sum is σ = 49318629416. Its totient is φ = 7045518480.

The previous prime is 21136555423. The next prime is 21136555457. The reversal of 21136555452 is 25455563112.

It is a tau number, because it is divible by the number of its divisors (12).

It is a self number, because there is not a number n which added to its sum of digits gives 21136555452.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21136555457) 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, 880689799 + ... + 880689822.

Almost surely, 2^21136555452 is an apocalyptic number.

It is an amenable number.

21136555452 is an abundant number, since it is smaller than the sum of its proper divisors (28182073964).

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

21136555452 is a wasteful number, since it uses less digits than its factorization.

21136555452 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1761379628 (or 1761379626 counting only the distinct ones).

The product of its digits is 180000, while the sum is 39.

The spelling of 21136555452 in words is "twenty-one billion, one hundred thirty-six million, five hundred fifty-five thousand, four hundred fifty-two".