21634679 has 6 divisors (see below), whose sum is σ = 23780400. Its totient is φ = 19667780.

The previous prime is 21634663. The next prime is 21634699. The reversal of 21634679 is 97643612.

It is not a de Polignac number, because 21634679 - 2⁴ = 21634663 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21634649) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 89279 + ... + 89520.

It is an arithmetic number, because the mean of its divisors is an integer number (3963400).

Almost surely, 2^21634679 is an apocalyptic number.

21634679 is a deficient number, since it is larger than the sum of its proper divisors (2145721).

21634679 is a wasteful number, since it uses less digits than its factorization.

21634679 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 178821 (or 178810 counting only the distinct ones).

The product of its digits is 54432, while the sum is 38.

The square root of 21634679 is about 4651.3093855387. The cubic root of 21634679 is about 278.6442926019.

The spelling of 21634679 in words is "twenty-one million, six hundred thirty-four thousand, six hundred seventy-nine".