21713888 has 96 divisors (see below), whose sum is σ = 52254720. Its totient is φ = 8686080.

The previous prime is 21713873. The next prime is 21713893. The reversal of 21713888 is 88831712.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 368003 + ... + 368061.

It is an arithmetic number, because the mean of its divisors is an integer number (544320).

Almost surely, 2^21713888 is an apocalyptic number.

21713888 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21713888, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26127360).

21713888 is an abundant number, since it is smaller than the sum of its proper divisors (30540832).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21713888 is a wasteful number, since it uses less digits than its factorization.

21713888 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 160 (or 152 counting only the distinct ones).

The product of its digits is 21504, while the sum is 38.

The square root of 21713888 is about 4659.8163053923. The cubic root of 21713888 is about 278.9839364175.

It can be divided in two parts, 217 and 13888, that multiplied together give a square (3013696 = 1736²).

The spelling of 21713888 in words is "twenty-one million, seven hundred thirteen thousand, eight hundred eighty-eight".