21708534 has 32 divisors (see below), whose sum is σ = 44478720. Its totient is φ = 7061600.

The previous prime is 21708523. The next prime is 21708539. The reversal of 21708534 is 43580712.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21708539) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 55612 + ... + 56000.

It is an arithmetic number, because the mean of its divisors is an integer number (1389960).

Almost surely, 2^21708534 is an apocalyptic number.

21708534 is an abundant number, since it is smaller than the sum of its proper divisors (22770186).

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

21708534 is a wasteful number, since it uses less digits than its factorization.

21708534 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 596.

The product of its (nonzero) digits is 6720, while the sum is 30.

The square root of 21708534 is about 4659.2417838099. The cubic root of 21708534 is about 278.9610048145.

The spelling of 21708534 in words is "twenty-one million, seven hundred eight thousand, five hundred thirty-four".