21375378 has 24 divisors (see below), whose sum is σ = 47911500. Its totient is φ = 6879264.

The previous prime is 21375373. The next prime is 21375379. The reversal of 21375378 is 87357312.

21375378 is a `hidden beast` number, since 213 + 75 + 378 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 21372129 + 3249 = 4623^2 + 57^2 .

It is not an unprimeable number, because it can be changed into a prime (21375371) 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, 19953 + ... + 20996.

Almost surely, 2^21375378 is an apocalyptic number.

21375378 is an abundant number, since it is smaller than the sum of its proper divisors (26536122).

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

21375378 is a wasteful number, since it uses less digits than its factorization.

21375378 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40986 (or 40983 counting only the distinct ones).

The product of its digits is 35280, while the sum is 36.

The square root of 21375378 is about 4623.3513818441. The cubic root of 21375378 is about 277.5265910725.

The spelling of 21375378 in words is "twenty-one million, three hundred seventy-five thousand, three hundred seventy-eight".