21682990 has 96 divisors (see below), whose sum is σ = 50971680. Its totient is φ = 6580224.

The previous prime is 21682987. The next prime is 21683017. The reversal of 21682990 is 9928612.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 158202 + ... + 158338.

It is an arithmetic number, because the mean of its divisors is an integer number (530955).

Almost surely, 2^21682990 is an apocalyptic number.

21682990 is an abundant number, since it is smaller than the sum of its proper divisors (29288690).

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

21682990 is a wasteful number, since it uses less digits than its factorization.

21682990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 194 (or 187 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 37.

The square root of 21682990 is about 4656.4997584022. The cubic root of 21682990 is about 278.8515459160.

The spelling of 21682990 in words is "twenty-one million, six hundred eighty-two thousand, nine hundred ninety".