21886724 has 6 divisors (see below), whose sum is σ = 38301774. Its totient is φ = 10943360.

The previous prime is 21886703. The next prime is 21886729. The reversal of 21886724 is 42768812.

It can be written as a sum of positive squares in only one way, i.e., 20866624 + 1020100 = 4568^2 + 1010^2 .

It is not an unprimeable number, because it can be changed into a prime (21886729) 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, 2735837 + ... + 2735844.

It is an arithmetic number, because the mean of its divisors is an integer number (6383629).

Almost surely, 2^21886724 is an apocalyptic number.

It is an amenable number.

21886724 is a deficient number, since it is larger than the sum of its proper divisors (16415050).

21886724 is a wasteful number, since it uses less digits than its factorization.

21886724 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5471685 (or 5471683 counting only the distinct ones).

The product of its digits is 43008, while the sum is 38.

The square root of 21886724 is about 4678.3249138981. The cubic root of 21886724 is about 279.7221904413.

The spelling of 21886724 in words is "twenty-one million, eight hundred eighty-six thousand, seven hundred twenty-four".