21311740 has 24 divisors (see below), whose sum is σ = 45012240. Its totient is φ = 8475648.

The previous prime is 21311737. The next prime is 21311747. The reversal of 21311740 is 4711312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21311747) 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, 604 + ... + 6556.

It is an arithmetic number, because the mean of its divisors is an integer number (1875510).

Almost surely, 2^21311740 is an apocalyptic number.

21311740 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21311740 is an abundant number, since it is smaller than the sum of its proper divisors (23700500).

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

21311740 is a wasteful number, since it uses less digits than its factorization.

21311740 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6141 (or 6139 counting only the distinct ones).

The product of its (nonzero) digits is 168, while the sum is 19.

The square root of 21311740 is about 4616.4640148061. The cubic root of 21311740 is about 277.2509032687.

The spelling of 21311740 in words is "twenty-one million, three hundred eleven thousand, seven hundred forty".