21131595552 has 96 divisors (see below), whose sum is σ = 59114022912. Its totient is φ = 6594224384.

The previous prime is 21131595547. The next prime is 21131595559. The reversal of 21131595552 is 25559513112.

It is a tau number, because it is divible by the number of its divisors (96).

It is a self number, because there is not a number n which added to its sum of digits gives 21131595552.

It is not an unprimeable number, because it can be changed into a prime (21131595559) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1963 + ... + 205589.

It is an arithmetic number, because the mean of its divisors is an integer number (615771072).

Almost surely, 2^21131595552 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21131595552, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29557011456).

21131595552 is an abundant number, since it is smaller than the sum of its proper divisors (37982427360).

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

21131595552 is a wasteful number, since it uses less digits than its factorization.

21131595552 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 203710 (or 203702 counting only the distinct ones).

The product of its digits is 67500, while the sum is 39.

It can be divided in two parts, 2113159 and 5552, that added together give a triangular number (2118711 = T₂₀₅₈).

The spelling of 21131595552 in words is "twenty-one billion, one hundred thirty-one million, five hundred ninety-five thousand, five hundred fifty-two".