21696539 has 8 divisors (see below), whose sum is σ = 23023440. Its totient is φ = 20375296.

The previous prime is 21696529. The next prime is 21696547. The reversal of 21696539 is 93569612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21696539 - 2¹⁶ = 21631003 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21696496 and 21696505.

It is not an unprimeable number, because it can be changed into a prime (21696529) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8552 + ... + 10794.

It is an arithmetic number, because the mean of its divisors is an integer number (2877930).

Almost surely, 2^21696539 is an apocalyptic number.

21696539 is a deficient number, since it is larger than the sum of its proper divisors (1326901).

21696539 is a wasteful number, since it uses less digits than its factorization.

21696539 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2829.

The product of its digits is 87480, while the sum is 41.

The square root of 21696539 is about 4657.9543793386. The cubic root of 21696539 is about 278.9096155968.

The spelling of 21696539 in words is "twenty-one million, six hundred ninety-six thousand, five hundred thirty-nine".