21742479 has 32 divisors (see below), whose sum is σ = 36998400. Its totient is φ = 12480480.

The previous prime is 21742471. The next prime is 21742481. The reversal of 21742479 is 97424712.

It is not a de Polignac number, because 21742479 - 2³ = 21742471 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21742471) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3717 + ... + 7569.

It is an arithmetic number, because the mean of its divisors is an integer number (1156200).

Almost surely, 2^21742479 is an apocalyptic number.

21742479 is a deficient number, since it is larger than the sum of its proper divisors (15255921).

21742479 is a wasteful number, since it uses less digits than its factorization.

21742479 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3892 (or 3886 counting only the distinct ones).

The product of its digits is 28224, while the sum is 36.

The square root of 21742479 is about 4662.8831209886. The cubic root of 21742479 is about 279.1063301499.

The spelling of 21742479 in words is "twenty-one million, seven hundred forty-two thousand, four hundred seventy-nine".