21489874 has 16 divisors (see below), whose sum is σ = 38779200. Its totient is φ = 8725104.

The previous prime is 21489833. The next prime is 21489877. The reversal of 21489874 is 47898412.

It is a self number, because there is not a number n which added to its sum of digits gives 21489874.

It is not an unprimeable number, because it can be changed into a prime (21489877) 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 in 7 ways as a sum of consecutive naturals, for example, 40129 + ... + 40660.

It is an arithmetic number, because the mean of its divisors is an integer number (2423700).

Almost surely, 2^21489874 is an apocalyptic number.

21489874 is a deficient number, since it is larger than the sum of its proper divisors (17289326).

21489874 is a wasteful number, since it uses less digits than its factorization.

21489874 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80817.

The product of its digits is 129024, while the sum is 43.

The square root of 21489874 is about 4635.7172044895. The cubic root of 21489874 is about 278.0212274390.

The spelling of 21489874 in words is "twenty-one million, four hundred eighty-nine thousand, eight hundred seventy-four".