21947634 has 12 divisors (see below), whose sum is σ = 47553246. Its totient is φ = 7315872.

The previous prime is 21947633. The next prime is 21947657. The reversal of 21947634 is 43674912.

21947634 is a `hidden beast` number, since 2 + 19 + 4 + 7 + 634 = 666.

It can be written as a sum of positive squares in only one way, i.e., 12006225 + 9941409 = 3465^2 + 3153^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21947633) 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, 609639 + ... + 609674.

Almost surely, 2^21947634 is an apocalyptic number.

21947634 is an abundant number, since it is smaller than the sum of its proper divisors (25605612).

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

21947634 is a wasteful number, since it uses less digits than its factorization.

21947634 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1219321 (or 1219318 counting only the distinct ones).

The product of its digits is 36288, while the sum is 36.

The square root of 21947634 is about 4684.8301996977. The cubic root of 21947634 is about 279.9814358440.

The spelling of 21947634 in words is "twenty-one million, nine hundred forty-seven thousand, six hundred thirty-four".