21495618 has 20 divisors (see below), whose sum is σ = 48166470. Its totient is φ = 7165152.

The previous prime is 21495613. The next prime is 21495619. The reversal of 21495618 is 81659412.

It can be written as a sum of positive squares in only one way, i.e., 21316689 + 178929 = 4617^2 + 423^2 .

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21495611) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 66183 + ... + 66506.

Almost surely, 2^21495618 is an apocalyptic number.

21495618 is an abundant number, since it is smaller than the sum of its proper divisors (26670852).

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

21495618 is a wasteful number, since it uses less digits than its factorization.

21495618 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132703 (or 132694 counting only the distinct ones).

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

The square root of 21495618 is about 4636.3367004565. The cubic root of 21495618 is about 278.0459958744.

The spelling of 21495618 in words is "twenty-one million, four hundred ninety-five thousand, six hundred eighteen".