21089518 has 4 divisors (see below), whose sum is σ = 31634280. Its totient is φ = 10544758.

The previous prime is 21089501. The next prime is 21089521. The reversal of 21089518 is 81598012.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5272378 + ... + 5272381.

It is an arithmetic number, because the mean of its divisors is an integer number (7908570).

Almost surely, 2^21089518 is an apocalyptic number.

21089518 is a deficient number, since it is larger than the sum of its proper divisors (10544762).

21089518 is a wasteful number, since it uses less digits than its factorization.

21089518 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10544761.

The product of its (nonzero) digits is 5760, while the sum is 34.

The square root of 21089518 is about 4592.3325228036. The cubic root of 21089518 is about 276.2838831517.

The spelling of 21089518 in words is "twenty-one million, eighty-nine thousand, five hundred eighteen".