21937378 has 16 divisors (see below), whose sum is σ = 35693784. Its totient is φ = 10071040.

The previous prime is 21937373. The next prime is 21937379. The reversal of 21937378 is 87373912.

It can be written as a sum of positive squares in 4 ways, for example, as 20187049 + 1750329 = 4493^2 + 1323^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21937378.

It is not an unprimeable number, because it can be changed into a prime (21937373) 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, 6475 + ... + 9262.

Almost surely, 2^21937378 is an apocalyptic number.

21937378 is a deficient number, since it is larger than the sum of its proper divisors (13756406).

21937378 is a wasteful number, since it uses less digits than its factorization.

21937378 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15797.

The product of its digits is 63504, while the sum is 40.

The square root of 21937378 is about 4683.7354750242. The cubic root of 21937378 is about 279.9378178243.

The spelling of 21937378 in words is "twenty-one million, nine hundred thirty-seven thousand, three hundred seventy-eight".