21377320 has 32 divisors (see below), whose sum is σ = 48764520. Its totient is φ = 8432640.

The previous prime is 21377311. The next prime is 21377329. The reversal of 21377320 is 2377312.

It is an interprime number because it is at equal distance from previous prime (21377311) and next prime (21377329).

It can be written as a sum of positive squares in 4 ways, for example, as 10074276 + 11303044 = 3174^2 + 3362^2 .

It is not an unprimeable number, because it can be changed into a prime (21377329) 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, 741 + ... + 6580.

Almost surely, 2^21377320 is an apocalyptic number.

21377320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21377320 is an abundant number, since it is smaller than the sum of its proper divisors (27387200).

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

21377320 is a wasteful number, since it uses less digits than its factorization.

21377320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7405 (or 7401 counting only the distinct ones).

The product of its (nonzero) digits is 1764, while the sum is 25.

The square root of 21377320 is about 4623.5613978837. The cubic root of 21377320 is about 277.5349954513.

The spelling of 21377320 in words is "twenty-one million, three hundred seventy-seven thousand, three hundred twenty".