21943998 has 12 divisors (see below), whose sum is σ = 47545368. Its totient is φ = 7314660.

The previous prime is 21943973. The next prime is 21944009. The reversal of 21943998 is 89934912.

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 5 ways as a sum of consecutive naturals, for example, 609538 + ... + 609573.

It is an arithmetic number, because the mean of its divisors is an integer number (3962114).

Almost surely, 2^21943998 is an apocalyptic number.

21943998 is an abundant number, since it is smaller than the sum of its proper divisors (25601370).

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

21943998 is a wasteful number, since it uses less digits than its factorization.

21943998 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1219119 (or 1219116 counting only the distinct ones).

The product of its digits is 139968, while the sum is 45.

The square root of 21943998 is about 4684.4421226012. The cubic root of 21943998 is about 279.9659737564.

The spelling of 21943998 in words is "twenty-one million, nine hundred forty-three thousand, nine hundred ninety-eight".