21974918 has 8 divisors (see below), whose sum is σ = 37671312. Its totient is φ = 9417816.

The previous prime is 21974917. The next prime is 21974921. The reversal of 21974918 is 81947912.

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

It is a super-2 number, since 2×21974918² = 965794042213448, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21974917) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 784805 + ... + 784832.

It is an arithmetic number, because the mean of its divisors is an integer number (4708914).

Almost surely, 2^21974918 is an apocalyptic number.

21974918 is a deficient number, since it is larger than the sum of its proper divisors (15696394).

21974918 is a wasteful number, since it uses less digits than its factorization.

21974918 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1569646.

The product of its digits is 36288, while the sum is 41.

The square root of 21974918 is about 4687.7412471253. The cubic root of 21974918 is about 280.0974065864.

The spelling of 21974918 in words is "twenty-one million, nine hundred seventy-four thousand, nine hundred eighteen".