21975147 has 6 divisors (see below), whose sum is σ = 31741892. Its totient is φ = 14650092.

The previous prime is 21975137. The next prime is 21975157. The reversal of 21975147 is 74157912.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21975137) and next prime (21975157).

It is not a de Polignac number, because 21975147 - 2⁴ = 21975131 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21975137) 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 5 ways as a sum of consecutive naturals, for example, 1220833 + ... + 1220850.

Almost surely, 2^21975147 is an apocalyptic number.

21975147 is a deficient number, since it is larger than the sum of its proper divisors (9766745).

21975147 is a wasteful number, since it uses less digits than its factorization.

21975147 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2441689 (or 2441686 counting only the distinct ones).

The product of its digits is 17640, while the sum is 36.

The square root of 21975147 is about 4687.7656724713. The cubic root of 21975147 is about 280.0983795454.

It can be divided in two parts, 21975 and 147, that added together give a palindrome (22122).

The spelling of 21975147 in words is "twenty-one million, nine hundred seventy-five thousand, one hundred forty-seven".