21998376 has 24 divisors (see below), whose sum is σ = 59579130. Its totient is φ = 7332768.

The previous prime is 21998359. The next prime is 21998381. The reversal of 21998376 is 67389912.

It can be written as a sum of positive squares in only one way, i.e., 21846276 + 152100 = 4674^2 + 390^2 .

It is a tau number, because it is divible by the number of its divisors (24).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 152695 + ... + 152838.

Almost surely, 2^21998376 is an apocalyptic number.

It is an amenable number.

21998376 is an abundant number, since it is smaller than the sum of its proper divisors (37580754).

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

21998376 is a wasteful number, since it uses less digits than its factorization.

21998376 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 305545 (or 305538 counting only the distinct ones).

The product of its digits is 163296, while the sum is 45.

The square root of 21998376 is about 4690.2426376468. The cubic root of 21998376 is about 280.1970381809.

The spelling of 21998376 in words is "twenty-one million, nine hundred ninety-eight thousand, three hundred seventy-six".