21685722 has 16 divisors (see below), whose sum is σ = 43475520. Its totient is φ = 7211232.

The previous prime is 21685721. The next prime is 21685733. The reversal of 21685722 is 22758612.

It is a super-2 number, since 2×21685722² = 940541077322568, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21685721) 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, 1483 + ... + 6750.

It is an arithmetic number, because the mean of its divisors is an integer number (2717220).

Almost surely, 2^21685722 is an apocalyptic number.

21685722 is an abundant number, since it is smaller than the sum of its proper divisors (21789798).

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

21685722 is a wasteful number, since it uses less digits than its factorization.

21685722 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8677.

The product of its digits is 13440, while the sum is 33.

The square root of 21685722 is about 4656.7931025546. The cubic root of 21685722 is about 278.8632569459.

The spelling of 21685722 in words is "twenty-one million, six hundred eighty-five thousand, seven hundred twenty-two".