21887144 has 16 divisors (see below), whose sum is σ = 41104320. Its totient is φ = 10926000.

The previous prime is 21887119. The next prime is 21887149. The reversal of 21887144 is 44178812.

It is a Smith number, since the sum of its digits (35) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (21887149) 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 3 ways as a sum of consecutive naturals, for example, 4187 + ... + 7829.

It is an arithmetic number, because the mean of its divisors is an integer number (2569020).

Almost surely, 2^21887144 is an apocalyptic number.

It is an amenable number.

21887144 is a deficient number, since it is larger than the sum of its proper divisors (19217176).

21887144 is a wasteful number, since it uses less digits than its factorization.

21887144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4400 (or 4396 counting only the distinct ones).

The product of its digits is 14336, while the sum is 35.

The square root of 21887144 is about 4678.3698015441. The cubic root of 21887144 is about 279.7239796929.

The spelling of 21887144 in words is "twenty-one million, eight hundred eighty-seven thousand, one hundred forty-four".