21312198 has 12 divisors (see below), whose sum is σ = 46176468. Its totient is φ = 7104060.

The previous prime is 21312173. The next prime is 21312223. The reversal of 21312198 is 89121312.

It is an interprime number because it is at equal distance from previous prime (21312173) and next prime (21312223).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 591988 + ... + 592023.

It is an arithmetic number, because the mean of its divisors is an integer number (3848039).

Almost surely, 2^21312198 is an apocalyptic number.

21312198 is an abundant number, since it is smaller than the sum of its proper divisors (24864270).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21312198 is a wasteful number, since it uses less digits than its factorization.

21312198 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1184019 (or 1184016 counting only the distinct ones).

The product of its digits is 864, while the sum is 27.

The square root of 21312198 is about 4616.5136196052. The cubic root of 21312198 is about 277.2528893416.

The spelling of 21312198 in words is "twenty-one million, three hundred twelve thousand, one hundred ninety-eight".