21212875 has 16 divisors (see below), whose sum is σ = 26627328. Its totient is φ = 16872000.

The previous prime is 21212869. The next prime is 21212887. The reversal of 21212875 is 57821212.

It is not a de Polignac number, because 21212875 - 2¹³ = 21204683 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27495 + ... + 28255.

It is an arithmetic number, because the mean of its divisors is an integer number (1664208).

Almost surely, 2^21212875 is an apocalyptic number.

21212875 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21212875 is a deficient number, since it is larger than the sum of its proper divisors (5414453).

21212875 is an equidigital number, since it uses as much as digits as its factorization.

21212875 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 999 (or 989 counting only the distinct ones).

The product of its digits is 2240, while the sum is 28.

The square root of 21212875 is about 4605.7436967335. The cubic root of 21212875 is about 276.8215169979.

The spelling of 21212875 in words is "twenty-one million, two hundred twelve thousand, eight hundred seventy-five".