21815682 has 24 divisors (see below), whose sum is σ = 50755536. Its totient is φ = 6232968.

The previous prime is 21815671. The next prime is 21815683. The reversal of 21815682 is 28651812.

It is a super-2 number, since 2×21815682² = 951847962250248, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21815683) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 36808 + ... + 37395.

It is an arithmetic number, because the mean of its divisors is an integer number (2114814).

Almost surely, 2^21815682 is an apocalyptic number.

21815682 is an abundant number, since it is smaller than the sum of its proper divisors (28939854).

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

21815682 is a wasteful number, since it uses less digits than its factorization.

21815682 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74222 (or 74215 counting only the distinct ones).

The product of its digits is 7680, while the sum is 33.

The square root of 21815682 is about 4670.7260677543. The cubic root of 21815682 is about 279.4192128076.

The spelling of 21815682 in words is "twenty-one million, eight hundred fifteen thousand, six hundred eighty-two".