21254975 has 18 divisors (see below), whose sum is σ = 30660984. Its totient is φ = 14574000.

The previous prime is 21254963. The next prime is 21254993. The reversal of 21254975 is 57945212.

It is a de Polignac number, because none of the positive numbers 2^k-21254975 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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 17 ways as a sum of consecutive naturals, for example, 7451 + ... + 9900.

It is an arithmetic number, because the mean of its divisors is an integer number (1703388).

Almost surely, 2^21254975 is an apocalyptic number.

21254975 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21254975 is a deficient number, since it is larger than the sum of its proper divisors (9406009).

21254975 is a wasteful number, since it uses less digits than its factorization.

21254975 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17375 (or 17363 counting only the distinct ones).

The product of its digits is 25200, while the sum is 35.

The square root of 21254975 is about 4610.3118115806. The cubic root of 21254975 is about 277.0045266804.

The spelling of 21254975 in words is "twenty-one million, two hundred fifty-four thousand, nine hundred seventy-five".