21389380 has 24 divisors (see below), whose sum is σ = 46368000. Its totient is φ = 8279520.

The previous prime is 21389377. The next prime is 21389393. The reversal of 21389380 is 8398312.

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, 16630 + ... + 17869.

It is an arithmetic number, because the mean of its divisors is an integer number (1932000).

Almost surely, 2^21389380 is an apocalyptic number.

21389380 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21389380 is an abundant number, since it is smaller than the sum of its proper divisors (24978620).

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

21389380 is a wasteful number, since it uses less digits than its factorization.

21389380 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34539 (or 34537 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 34.

The square root of 21389380 is about 4624.8654034469. The cubic root of 21389380 is about 277.5871760306.

The spelling of 21389380 in words is "twenty-one million, three hundred eighty-nine thousand, three hundred eighty".