21891974 has 16 divisors (see below), whose sum is σ = 35607600. Its totient is φ = 10034400.

The previous prime is 21891973. The next prime is 21891977. The reversal of 21891974 is 47919812.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21891973) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1049 + ... + 6699.

It is an arithmetic number, because the mean of its divisors is an integer number (2225475).

Almost surely, 2^21891974 is an apocalyptic number.

21891974 is a deficient number, since it is larger than the sum of its proper divisors (13715626).

21891974 is a wasteful number, since it uses less digits than its factorization.

21891974 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5815.

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

The square root of 21891974 is about 4678.8859785210. The cubic root of 21891974 is about 279.7445544414.

The spelling of 21891974 in words is "twenty-one million, eight hundred ninety-one thousand, nine hundred seventy-four".