21969975 has 12 divisors (see below), whose sum is σ = 36323816. Its totient is φ = 11717280.

The previous prime is 21969919. The next prime is 21969977. The reversal of 21969975 is 57996912.

It is not a de Polignac number, because 21969975 - 2⁶ = 21969911 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21969977) 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, 146392 + ... + 146541.

Almost surely, 2^21969975 is an apocalyptic number.

21969975 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21969975 is a deficient number, since it is larger than the sum of its proper divisors (14353841).

21969975 is a wasteful number, since it uses less digits than its factorization.

21969975 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 292946 (or 292941 counting only the distinct ones).

The product of its digits is 306180, while the sum is 48.

The square root of 21969975 is about 4687.2139912746. The cubic root of 21969975 is about 280.0764034697.

The spelling of 21969975 in words is "twenty-one million, nine hundred sixty-nine thousand, nine hundred seventy-five".