21978362 has 24 divisors (see below), whose sum is σ = 38653524. Its totient is φ = 9344832.

The previous prime is 21978343. The next prime is 21978373. The reversal of 21978362 is 26387912.

It can be written as a sum of positive squares in 2 ways, for example, as 20511841 + 1466521 = 4529^2 + 1211^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 12608 + ... + 14244.

Almost surely, 2^21978362 is an apocalyptic number.

21978362 is a deficient number, since it is larger than the sum of its proper divisors (16675162).

21978362 is a wasteful number, since it uses less digits than its factorization.

21978362 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1790 (or 1783 counting only the distinct ones).

The product of its digits is 36288, while the sum is 38.

The square root of 21978362 is about 4688.1085738280. The cubic root of 21978362 is about 280.1120384966.

The spelling of 21978362 in words is "twenty-one million, nine hundred seventy-eight thousand, three hundred sixty-two".