21998374 has 8 divisors (see below), whose sum is σ = 34938648. Its totient is φ = 10352160.

The previous prime is 21998359. The next prime is 21998381. The reversal of 21998374 is 47389912.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 21998374.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 323472 + ... + 323539.

It is an arithmetic number, because the mean of its divisors is an integer number (4367331).

Almost surely, 2^21998374 is an apocalyptic number.

21998374 is a deficient number, since it is larger than the sum of its proper divisors (12940274).

21998374 is a wasteful number, since it uses less digits than its factorization.

21998374 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 647030.

The product of its digits is 108864, while the sum is 43.

The square root of 21998374 is about 4690.2424244382. The cubic root of 21998374 is about 280.1970296895.

The spelling of 21998374 in words is "twenty-one million, nine hundred ninety-eight thousand, three hundred seventy-four".