21157888 has 24 divisors (see below), whose sum is σ = 42309540. Its totient is φ = 10577920.

The previous prime is 21157883. The next prime is 21157891. The reversal of 21157888 is 88875112.

It is a self number, because there is not a number n which added to its sum of digits gives 21157888.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21157883) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3118 + ... + 7213.

Almost surely, 2^21157888 is an apocalyptic number.

It is an amenable number.

21157888 is a deficient number, since it is larger than the sum of its proper divisors (21151652).

21157888 is an equidigital number, since it uses as much as digits as its factorization.

21157888 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10353 (or 10333 counting only the distinct ones).

The product of its digits is 35840, while the sum is 40.

The square root of 21157888 is about 4599.7704290540. The cubic root of 21157888 is about 276.5821221972.

The spelling of 21157888 in words is "twenty-one million, one hundred fifty-seven thousand, eight hundred eighty-eight".