21931704 has 48 divisors (see below), whose sum is σ = 60671520. Its totient is φ = 7153920.

The previous prime is 21931703. The next prime is 21931709. The reversal of 21931704 is 40713912.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21931703) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 144 + ... + 6624.

It is an arithmetic number, because the mean of its divisors is an integer number (1263990).

Almost surely, 2^21931704 is an apocalyptic number.

21931704 is a gapful number since it is divisible by the number (24) 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 21931704, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30335760).

21931704 is an abundant number, since it is smaller than the sum of its proper divisors (38739816).

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

21931704 is a wasteful number, since it uses less digits than its factorization.

21931704 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6540 (or 6533 counting only the distinct ones).

The product of its (nonzero) digits is 1512, while the sum is 27.

The square root of 21931704 is about 4683.1297227388. The cubic root of 21931704 is about 279.9136808750.

The spelling of 21931704 in words is "twenty-one million, nine hundred thirty-one thousand, seven hundred four".