21971075 has 24 divisors (see below), whose sum is σ = 31331328. Its totient is φ = 14971680.

The previous prime is 21971063. The next prime is 21971083. The reversal of 21971075 is 57017912.

It is not a de Polignac number, because 21971075 - 2¹⁰ = 21970051 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 38744 + ... + 39306.

It is an arithmetic number, because the mean of its divisors is an integer number (1305472).

Almost surely, 2^21971075 is an apocalyptic number.

21971075 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21971075 is a deficient number, since it is larger than the sum of its proper divisors (9360253).

21971075 is a wasteful number, since it uses less digits than its factorization.

21971075 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 803 (or 798 counting only the distinct ones).

The product of its (nonzero) digits is 4410, while the sum is 32.

The square root of 21971075 is about 4687.3313302987. The cubic root of 21971075 is about 280.0810777111.

Adding to 21971075 its reverse (57017912), we get a palindrome (78988987).

The spelling of 21971075 in words is "twenty-one million, nine hundred seventy-one thousand, seventy-five".