21958998 has 16 divisors (see below), whose sum is σ = 44474880. Its totient is φ = 7226856.

The previous prime is 21958991. The next prime is 21959009. The reversal of 21958998 is 89985912.

It is a self number, because there is not a number n which added to its sum of digits gives 21958998.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21958991) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22690 + ... + 23637.

It is an arithmetic number, because the mean of its divisors is an integer number (2779680).

Almost surely, 2^21958998 is an apocalyptic number.

21958998 is an abundant number, since it is smaller than the sum of its proper divisors (22515882).

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

21958998 is a wasteful number, since it uses less digits than its factorization.

21958998 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46411.

The product of its digits is 466560, while the sum is 51.

The square root of 21958998 is about 4686.0428935297. The cubic root of 21958998 is about 280.0297502403.

The spelling of 21958998 in words is "twenty-one million, nine hundred fifty-eight thousand, nine hundred ninety-eight".