21891198 has 32 divisors (see below), whose sum is σ = 51393024. Its totient is φ = 6085152.

The previous prime is 21891187. The next prime is 21891203. The reversal of 21891198 is 89119812.

It is a super-3 number, since 3×21891198³ (a number of 23 digits) contains 333 as substring.

It is a Curzon number.

It is a congruent 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, 5490 + ... + 8597.

It is an arithmetic number, because the mean of its divisors is an integer number (1606032).

Almost surely, 2^21891198 is an apocalyptic number.

21891198 is an abundant number, since it is smaller than the sum of its proper divisors (29501826).

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

21891198 is a wasteful number, since it uses less digits than its factorization.

21891198 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14136.

The product of its digits is 10368, while the sum is 39.

The square root of 21891198 is about 4678.8030520636. The cubic root of 21891198 is about 279.7412490544.

The spelling of 21891198 in words is "twenty-one million, eight hundred ninety-one thousand, one hundred ninety-eight".