21360818 has 4 divisors (see below), whose sum is σ = 32041230. Its totient is φ = 10680408.

The previous prime is 21360817. The next prime is 21360827. The reversal of 21360818 is 81806312.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 17530969 + 3829849 = 4187^2 + 1957^2 .

It is not an unprimeable number, because it can be changed into a prime (21360811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5340203 + ... + 5340206.

Almost surely, 2^21360818 is an apocalyptic number.

21360818 is a deficient number, since it is larger than the sum of its proper divisors (10680412).

21360818 is a wasteful number, since it uses less digits than its factorization.

21360818 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10680411.

The product of its (nonzero) digits is 2304, while the sum is 29.

The square root of 21360818 is about 4621.7764982742. The cubic root of 21360818 is about 277.4635636493.

The spelling of 21360818 in words is "twenty-one million, three hundred sixty thousand, eight hundred eighteen".