21367720 has 32 divisors (see below), whose sum is σ = 52449120. Its totient is φ = 7769920.

The previous prime is 21367699. The next prime is 21367721. The reversal of 21367720 is 2776312.

It is not an unprimeable number, because it can be changed into a prime (21367721) 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, 23842 + ... + 24721.

It is an arithmetic number, because the mean of its divisors is an integer number (1639035).

Almost surely, 2^21367720 is an apocalyptic number.

21367720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21367720 is an abundant number, since it is smaller than the sum of its proper divisors (31081400).

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

21367720 is a wasteful number, since it uses less digits than its factorization.

21367720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48585 (or 48581 counting only the distinct ones).

The product of its (nonzero) digits is 3528, while the sum is 28.

The square root of 21367720 is about 4622.5231205479. The cubic root of 21367720 is about 277.4934446413.

The spelling of 21367720 in words is "twenty-one million, three hundred sixty-seven thousand, seven hundred twenty".