21953975 has 6 divisors (see below), whose sum is σ = 27222960. Its totient is φ = 17563160.

The previous prime is 21953969. The next prime is 21953989. The reversal of 21953975 is 57935912.

It is not a de Polignac number, because 21953975 - 2²² = 17759671 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 439055 + ... + 439104.

It is an arithmetic number, because the mean of its divisors is an integer number (4537160).

Almost surely, 2^21953975 is an apocalyptic number.

21953975 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21953975 is a deficient number, since it is larger than the sum of its proper divisors (5268985).

21953975 is an equidigital number, since it uses as much as digits as its factorization.

21953975 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 878169 (or 878164 counting only the distinct ones).

The product of its digits is 85050, while the sum is 41.

The square root of 21953975 is about 4685.5069096097. The cubic root of 21953975 is about 280.0083968570.

The spelling of 21953975 in words is "twenty-one million, nine hundred fifty-three thousand, nine hundred seventy-five".