21459618 has 12 divisors (see below), whose sum is σ = 46495878. Its totient is φ = 7153200.

The previous prime is 21459611. The next prime is 21459629. The reversal of 21459618 is 81695412.

It can be written as a sum of positive squares in only one way, i.e., 19954089 + 1505529 = 4467^2 + 1227^2 .

It is not an unprimeable number, because it can be changed into a prime (21459611) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 596083 + ... + 596118.

Almost surely, 2^21459618 is an apocalyptic number.

21459618 is an abundant number, since it is smaller than the sum of its proper divisors (25036260).

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

21459618 is a wasteful number, since it uses less digits than its factorization.

21459618 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1192209 (or 1192206 counting only the distinct ones).

The product of its digits is 17280, while the sum is 36.

The square root of 21459618 is about 4632.4526980855. The cubic root of 21459618 is about 277.8906890427.

The spelling of 21459618 in words is "twenty-one million, four hundred fifty-nine thousand, six hundred eighteen".