21881368 has 16 divisors (see below), whose sum is σ = 41802480. Its totient is φ = 10734048.

The previous prime is 21881359. The next prime is 21881383. The reversal of 21881368 is 86318812.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 25380 + ... + 26227.

It is an arithmetic number, because the mean of its divisors is an integer number (2612655).

Almost surely, 2^21881368 is an apocalyptic number.

It is an amenable number.

21881368 is a deficient number, since it is larger than the sum of its proper divisors (19921112).

21881368 is a wasteful number, since it uses less digits than its factorization.

21881368 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51666 (or 51662 counting only the distinct ones).

The product of its digits is 18432, while the sum is 37.

The square root of 21881368 is about 4677.7524517657. The cubic root of 21881368 is about 279.6993712157.

The spelling of 21881368 in words is "twenty-one million, eight hundred eighty-one thousand, three hundred sixty-eight".