21252194487972 has 36 divisors (see below), whose sum is σ = 61395228521536. Its totient is φ = 6072055567920.

The previous prime is 21252194487967. The next prime is 21252194488037. The reversal of 21252194487972 is 27978449125212.

21252194487972 is a `hidden beast` number, since 2 + 1 + 2 + 52 + 1 + 9 + 448 + 79 + 72 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (63).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 42167052304 + ... + 42167052807.

Almost surely, 2^{21252194487972} is an apocalyptic number.

It is an amenable number.

21252194487972 is an abundant number, since it is smaller than the sum of its proper divisors (40143034033564).

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

21252194487972 is a wasteful number, since it uses less digits than its factorization.

21252194487972 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84334105128 (or 84334105123 counting only the distinct ones).

The product of its digits is 40642560, while the sum is 63.

The spelling of 21252194487972 in words is "twenty-one trillion, two hundred fifty-two billion, one hundred ninety-four million, four hundred eighty-seven thousand, nine hundred seventy-two".