21911736 has 128 divisors (see below), whose sum is σ = 69672960. Its totient is φ = 5577600.

The previous prime is 21911713. The next prime is 21911741. The reversal of 21911736 is 63711912.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 131125 + ... + 131291.

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

Almost surely, 2^21911736 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21911736, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34836480).

21911736 is an abundant number, since it is smaller than the sum of its proper divisors (47761224).

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

21911736 is a wasteful number, since it uses less digits than its factorization.

21911736 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 265 (or 261 counting only the distinct ones).

The product of its digits is 2268, while the sum is 30.

The square root of 21911736 is about 4680.9973296297. The cubic root of 21911736 is about 279.8287047521.

The spelling of 21911736 in words is "twenty-one million, nine hundred eleven thousand, seven hundred thirty-six".