21999974 has 4 divisors (see below), whose sum is σ = 32999964. Its totient is φ = 10999986.

The previous prime is 21999973. The next prime is 21999977. The reversal of 21999974 is 47999912.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21999973) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5499992 + ... + 5499995.

It is an arithmetic number, because the mean of its divisors is an integer number (8249991).

Almost surely, 2^21999974 is an apocalyptic number.

21999974 is a deficient number, since it is larger than the sum of its proper divisors (10999990).

21999974 is a wasteful number, since it uses less digits than its factorization.

21999974 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10999989.

The product of its digits is 367416, while the sum is 50.

The square root of 21999974 is about 4690.4129882133. The cubic root of 21999974 is about 280.2038226821.

The spelling of 21999974 in words is "twenty-one million, nine hundred ninety-nine thousand, nine hundred seventy-four".