21979692 has 36 divisors (see below), whose sum is σ = 63497616. Its totient is φ = 6279840.

The previous prime is 21979681. The next prime is 21979693. The reversal of 21979692 is 29697912.

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

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (21979693) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 43359 + ... + 43862.

Almost surely, 2^21979692 is an apocalyptic number.

It is an amenable number.

21979692 is an abundant number, since it is smaller than the sum of its proper divisors (41517924).

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

21979692 is a wasteful number, since it uses less digits than its factorization.

21979692 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87238 (or 87233 counting only the distinct ones).

The product of its digits is 122472, while the sum is 45.

The square root of 21979692 is about 4688.2504199328. The cubic root of 21979692 is about 280.1176886218.

The spelling of 21979692 in words is "twenty-one million, nine hundred seventy-nine thousand, six hundred ninety-two".