21190618 has 4 divisors (see below), whose sum is σ = 31785930. Its totient is φ = 10595308.

The previous prime is 21190591. The next prime is 21190621. The reversal of 21190618 is 81609112.

It is a happy number.

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., 13198689 + 7991929 = 3633^2 + 2827^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5297653 + ... + 5297656.

Almost surely, 2^21190618 is an apocalyptic number.

21190618 is a deficient number, since it is larger than the sum of its proper divisors (10595312).

21190618 is a wasteful number, since it uses less digits than its factorization.

21190618 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10595311.

The product of its (nonzero) digits is 864, while the sum is 28.

The square root of 21190618 is about 4603.3268404492. The cubic root of 21190618 is about 276.7246674417.

The spelling of 21190618 in words is "twenty-one million, one hundred ninety thousand, six hundred eighteen".