21947156 has 24 divisors (see below), whose sum is σ = 47885376. Its totient is φ = 8550720.

The previous prime is 21947117. The next prime is 21947161. The reversal of 21947156 is 65174912.

It is a Smith number, since the sum of its digits (35) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 35321 + ... + 35936.

It is an arithmetic number, because the mean of its divisors is an integer number (1995224).

Almost surely, 2^21947156 is an apocalyptic number.

It is an amenable number.

21947156 is an abundant number, since it is smaller than the sum of its proper divisors (25938220).

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

21947156 is a wasteful number, since it uses less digits than its factorization.

21947156 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71279 (or 71277 counting only the distinct ones).

The product of its digits is 15120, while the sum is 35.

The square root of 21947156 is about 4684.7791836969. The cubic root of 21947156 is about 279.9794032468.

The spelling of 21947156 in words is "twenty-one million, nine hundred forty-seven thousand, one hundred fifty-six".