21693975 has 12 divisors (see below), whose sum is σ = 35867496. Its totient is φ = 11570080.

The previous prime is 21693967. The next prime is 21693977. The reversal of 21693975 is 57939612.

It is not a de Polignac number, because 21693975 - 2³ = 21693967 is a prime.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21693977) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 144552 + ... + 144701.

It is an arithmetic number, because the mean of its divisors is an integer number (2988958).

Almost surely, 2^21693975 is an apocalyptic number.

21693975 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21693975 is a deficient number, since it is larger than the sum of its proper divisors (14173521).

21693975 is a wasteful number, since it uses less digits than its factorization.

21693975 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 289266 (or 289261 counting only the distinct ones).

The product of its digits is 102060, while the sum is 42.

The square root of 21693975 is about 4657.6791430926. The cubic root of 21693975 is about 278.8986284000.

The spelling of 21693975 in words is "twenty-one million, six hundred ninety-three thousand, nine hundred seventy-five".