21713340 has 96 divisors (see below), whose sum is σ = 67060224. Its totient is φ = 5205760.

The previous prime is 21713297. The next prime is 21713359. The reversal of 21713340 is 4331712.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 110122 + ... + 110318.

It is an arithmetic number, because the mean of its divisors is an integer number (698544).

Almost surely, 2^21713340 is an apocalyptic number.

21713340 is a gapful number since it is divisible by the number (20) 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 21713340, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33530112).

21713340 is an abundant number, since it is smaller than the sum of its proper divisors (45346884).

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

21713340 is a wasteful number, since it uses less digits than its factorization.

21713340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 387 (or 385 counting only the distinct ones).

The product of its (nonzero) digits is 504, while the sum is 21.

The square root of 21713340 is about 4659.7575044202. The cubic root of 21713340 is about 278.9815894636.

The spelling of 21713340 in words is "twenty-one million, seven hundred thirteen thousand, three hundred forty".