21938775 has 12 divisors (see below), whose sum is σ = 36272232. Its totient is φ = 11700640.

The previous prime is 21938773. The next prime is 21938779. The reversal of 21938775 is 57783912.

It is not a de Polignac number, because 21938775 - 2¹ = 21938773 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21938771) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 146184 + ... + 146333.

It is an arithmetic number, because the mean of its divisors is an integer number (3022686).

Almost surely, 2^21938775 is an apocalyptic number.

21938775 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21938775 is a deficient number, since it is larger than the sum of its proper divisors (14333457).

21938775 is a wasteful number, since it uses less digits than its factorization.

21938775 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 292530 (or 292525 counting only the distinct ones).

The product of its digits is 105840, while the sum is 42.

The square root of 21938775 is about 4683.8846057519. The cubic root of 21938775 is about 279.9437599630.

The spelling of 21938775 in words is "twenty-one million, nine hundred thirty-eight thousand, seven hundred seventy-five".