21880971 has 12 divisors (see below), whose sum is σ = 36121072. Its totient is φ = 12503376.

The previous prime is 21880967. The next prime is 21880973. The reversal of 21880971 is 17908812.

It is not a de Polignac number, because 21880971 - 2² = 21880967 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21880973) 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, 173596 + ... + 173721.

Almost surely, 2^21880971 is an apocalyptic number.

21880971 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21880971 is a deficient number, since it is larger than the sum of its proper divisors (14240101).

21880971 is a wasteful number, since it uses less digits than its factorization.

21880971 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 347330 (or 347327 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 36.

The square root of 21880971 is about 4677.7100166641. The cubic root of 21880971 is about 279.6976796499.

The spelling of 21880971 in words is "twenty-one million, eight hundred eighty thousand, nine hundred seventy-one".