21198180072 has 64 divisors (see below), whose sum is σ = 55807027200. Its totient is φ = 6691481280.

The previous prime is 21198180061. The next prime is 21198180173. The reversal of 21198180072 is 27008189112.

It is a self number, because there is not a number n which added to its sum of digits gives 21198180072.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1346953 + ... + 1362599.

It is an arithmetic number, because the mean of its divisors is an integer number (871984800).

Almost surely, 2^21198180072 is an apocalyptic number.

It is an amenable number.

21198180072 is an abundant number, since it is smaller than the sum of its proper divisors (34608847128).

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

21198180072 is a wasteful number, since it uses less digits than its factorization.

21198180072 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18646 (or 18642 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 39.

The spelling of 21198180072 in words is "twenty-one billion, one hundred ninety-eight million, one hundred eighty thousand, seventy-two".