21687950 has 12 divisors (see below), whose sum is σ = 40339680. Its totient is φ = 8675160.

The previous prime is 21687931. The next prime is 21687959. The reversal of 21687950 is 5978612.

It is a hoax number, since the sum of its digits (38) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21687959) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 216830 + ... + 216929.

It is an arithmetic number, because the mean of its divisors is an integer number (3361640).

Almost surely, 2^21687950 is an apocalyptic number.

21687950 is a deficient number, since it is larger than the sum of its proper divisors (18651730).

21687950 is a wasteful number, since it uses less digits than its factorization.

21687950 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 433771 (or 433766 counting only the distinct ones).

The product of its (nonzero) digits is 30240, while the sum is 38.

The square root of 21687950 is about 4657.0323168301. The cubic root of 21687950 is about 278.8728067941.

The spelling of 21687950 in words is "twenty-one million, six hundred eighty-seven thousand, nine hundred fifty".