21918120232 has 8 divisors (see below), whose sum is σ = 41096475450. Its totient is φ = 10959060112.

The previous prime is 21918120229. The next prime is 21918120239. The reversal of 21918120232 is 23202181912.

It can be written as a sum of positive squares in only one way, i.e., 20922465316 + 995654916 = 144646^2 + 31554^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a junction number, because it is equal to n+sod(n) for n = 21918120194 and 21918120203.

It is not an unprimeable number, because it can be changed into a prime (21918120239) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1369882507 + ... + 1369882522.

Almost surely, 2^21918120232 is an apocalyptic number.

It is an amenable number.

21918120232 is a deficient number, since it is larger than the sum of its proper divisors (19178355218).

21918120232 is a wasteful number, since it uses less digits than its factorization.

21918120232 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2739765035 (or 2739765031 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 31.

The spelling of 21918120232 in words is "twenty-one billion, nine hundred eighteen million, one hundred twenty thousand, two hundred thirty-two".