21146975 has 6 divisors (see below), whose sum is σ = 26222280. Its totient is φ = 16917560.

The previous prime is 21146971. The next prime is 21146977. The reversal of 21146975 is 57964112.

It is not a de Polignac number, because 21146975 - 2² = 21146971 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21146971) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 422915 + ... + 422964.

It is an arithmetic number, because the mean of its divisors is an integer number (4370380).

Almost surely, 2^21146975 is an apocalyptic number.

21146975 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21146975 is a deficient number, since it is larger than the sum of its proper divisors (5075305).

21146975 is an equidigital number, since it uses as much as digits as its factorization.

21146975 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 845889 (or 845884 counting only the distinct ones).

The product of its digits is 15120, while the sum is 35.

The square root of 21146975 is about 4598.5840211961. The cubic root of 21146975 is about 276.5345613728.

The spelling of 21146975 in words is "twenty-one million, one hundred forty-six thousand, nine hundred seventy-five".