21634523 has 8 divisors (see below), whose sum is σ = 23395392. Its totient is φ = 19927936.

The previous prime is 21634453. The next prime is 21634537. The reversal of 21634523 is 32543612.

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 21634523 - 2⁸ = 21634267 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21634492 and 21634501.

It is not an unprimeable number, because it can be changed into a prime (21634573) 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, 12740 + ... + 14337.

It is an arithmetic number, because the mean of its divisors is an integer number (2924424).

Almost surely, 2^21634523 is an apocalyptic number.

21634523 is a deficient number, since it is larger than the sum of its proper divisors (1760869).

21634523 is a wasteful number, since it uses less digits than its factorization.

21634523 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27141.

The product of its digits is 4320, while the sum is 26.

The square root of 21634523 is about 4651.2926160370. The cubic root of 21634523 is about 278.6436228652.

The spelling of 21634523 in words is "twenty-one million, six hundred thirty-four thousand, five hundred twenty-three".