21771948 has 48 divisors (see below), whose sum is σ = 58343040. Its totient is φ = 6249600.

The previous prime is 21771913. The next prime is 21771977. The reversal of 21771948 is 84917712.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1833 + ... + 6848.

It is an arithmetic number, because the mean of its divisors is an integer number (1215480).

Almost surely, 2^21771948 is an apocalyptic number.

It is an amenable number.

21771948 is an abundant number, since it is smaller than the sum of its proper divisors (36571092).

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

21771948 is a wasteful number, since it uses less digits than its factorization.

21771948 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8718 (or 8716 counting only the distinct ones).

The product of its digits is 28224, while the sum is 39.

The square root of 21771948 is about 4666.0420058118. The cubic root of 21771948 is about 279.2323702285.

The spelling of 21771948 in words is "twenty-one million, seven hundred seventy-one thousand, nine hundred forty-eight".