21651974 has 4 divisors (see below), whose sum is σ = 32477964. Its totient is φ = 10825986.

The previous prime is 21651967. The next prime is 21651979. The reversal of 21651974 is 47915612.

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 (21651979) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5412992 + ... + 5412995.

It is an arithmetic number, because the mean of its divisors is an integer number (8119491).

Almost surely, 2^21651974 is an apocalyptic number.

21651974 is a deficient number, since it is larger than the sum of its proper divisors (10825990).

21651974 is a wasteful number, since it uses less digits than its factorization.

21651974 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10825989.

The product of its digits is 15120, while the sum is 35.

The square root of 21651974 is about 4653.1681680335. The cubic root of 21651974 is about 278.7185232611.

The spelling of 21651974 in words is "twenty-one million, six hundred fifty-one thousand, nine hundred seventy-four".