21911320 has 32 divisors (see below), whose sum is σ = 49533120. Its totient is φ = 8723200.

The previous prime is 21911297. The next prime is 21911321. The reversal of 21911320 is 2311912.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21911321) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8145 + ... + 10495.

It is an arithmetic number, because the mean of its divisors is an integer number (1547910).

Almost surely, 2^21911320 is an apocalyptic number.

21911320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21911320 is an abundant number, since it is smaller than the sum of its proper divisors (27621800).

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

21911320 is a wasteful number, since it uses less digits than its factorization.

21911320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2595 (or 2591 counting only the distinct ones).

The product of its (nonzero) digits is 108, while the sum is 19.

The square root of 21911320 is about 4680.9528944436. The cubic root of 21911320 is about 279.8269338673.

The spelling of 21911320 in words is "twenty-one million, nine hundred eleven thousand, three hundred twenty".