21445975 has 6 divisors (see below), whose sum is σ = 26593040. Its totient is φ = 17156760.

The previous prime is 21445961. The next prime is 21445981. The reversal of 21445975 is 57954412.

It is not a de Polignac number, because 21445975 - 2⁵ = 21445943 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, 428895 + ... + 428944.

Almost surely, 2^21445975 is an apocalyptic number.

21445975 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21445975 is a deficient number, since it is larger than the sum of its proper divisors (5147065).

21445975 is an equidigital number, since it uses as much as digits as its factorization.

21445975 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 857849 (or 857844 counting only the distinct ones).

The product of its digits is 50400, while the sum is 37.

The square root of 21445975 is about 4630.9799179007. The cubic root of 21445975 is about 277.8317866834.

The spelling of 21445975 in words is "twenty-one million, four hundred forty-five thousand, nine hundred seventy-five".