21238660 has 24 divisors (see below), whose sum is σ = 46541376. Its totient is φ = 8125920.

The previous prime is 21238639. The next prime is 21238667. The reversal of 21238660 is 6683212.

It is not an unprimeable number, because it can be changed into a prime (21238667) 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, 22626 + ... + 23545.

It is an arithmetic number, because the mean of its divisors is an integer number (1939224).

Almost surely, 2^21238660 is an apocalyptic number.

21238660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21238660 is an abundant number, since it is smaller than the sum of its proper divisors (25302716).

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

21238660 is a wasteful number, since it uses less digits than its factorization.

21238660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46203 (or 46201 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 28.

The square root of 21238660 is about 4608.5420688109. The cubic root of 21238660 is about 276.9336336985.

The spelling of 21238660 in words is "twenty-one million, two hundred thirty-eight thousand, six hundred sixty".