21347680 has 48 divisors (see below), whose sum is σ = 52635744. Its totient is φ = 8166400.

The previous prime is 21347653. The next prime is 21347701. The reversal of 21347680 is 8674312.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 780 + ... + 6580.

It is an arithmetic number, because the mean of its divisors is an integer number (1096578).

Almost surely, 2^21347680 is an apocalyptic number.

21347680 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 21347680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26317872).

21347680 is an abundant number, since it is smaller than the sum of its proper divisors (31288064).

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

21347680 is a wasteful number, since it uses less digits than its factorization.

21347680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5839 (or 5831 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 31.

The square root of 21347680 is about 4620.3549647186. The cubic root of 21347680 is about 277.4066672030.

The spelling of 21347680 in words is "twenty-one million, three hundred forty-seven thousand, six hundred eighty".