21898998 has 40 divisors (see below), whose sum is σ = 53535240. Its totient is φ = 6635520.

The previous prime is 21898993. The next prime is 21899023. The reversal of 21898998 is 89989812.

It is a happy number.

It is a super-2 number, since 2×21898998² = 959132226808008, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21898993) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 4363 + ... + 7926.

It is an arithmetic number, because the mean of its divisors is an integer number (1338381).

Almost surely, 2^21898998 is an apocalyptic number.

21898998 is an abundant number, since it is smaller than the sum of its proper divisors (31636242).

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

21898998 is a wasteful number, since it uses less digits than its factorization.

21898998 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12314 (or 12305 counting only the distinct ones).

The product of its digits is 746496, while the sum is 54.

The square root of 21898998 is about 4679.6365243467. The cubic root of 21898998 is about 279.7744697526.

The spelling of 21898998 in words is "twenty-one million, eight hundred ninety-eight thousand, nine hundred ninety-eight".