21413640 has 32 divisors (see below), whose sum is σ = 64241280. Its totient is φ = 5710272.

The previous prime is 21413617. The next prime is 21413641. The reversal of 21413640 is 4631412.

It is not an unprimeable number, because it can be changed into a prime (21413641) 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, 89104 + ... + 89343.

It is an arithmetic number, because the mean of its divisors is an integer number (2007540).

Almost surely, 2^21413640 is an apocalyptic number.

21413640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21413640 is an abundant number, since it is smaller than the sum of its proper divisors (42827640).

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

21413640 is a wasteful number, since it uses less digits than its factorization.

21413640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 178461 (or 178457 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 21.

The square root of 21413640 is about 4627.4874392050. The cubic root of 21413640 is about 277.6920835513.

The spelling of 21413640 in words is "twenty-one million, four hundred thirteen thousand, six hundred forty".