21957974 has 4 divisors (see below), whose sum is σ = 32936964. Its totient is φ = 10978986.

The previous prime is 21957973. The next prime is 21957979. The reversal of 21957974 is 47975912.

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 (21957973) by changing a digit.

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 as a sum of consecutive naturals, namely, 5489492 + ... + 5489495.

It is an arithmetic number, because the mean of its divisors is an integer number (8234241).

Almost surely, 2^21957974 is an apocalyptic number.

21957974 is a deficient number, since it is larger than the sum of its proper divisors (10978990).

21957974 is a wasteful number, since it uses less digits than its factorization.

21957974 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10978989.

The product of its digits is 158760, while the sum is 44.

The square root of 21957974 is about 4685.9336316256. The cubic root of 21957974 is about 280.0253973561.

The spelling of 21957974 in words is "twenty-one million, nine hundred fifty-seven thousand, nine hundred seventy-four".