21610618 has 4 divisors (see below), whose sum is σ = 32415930. Its totient is φ = 10805308.

The previous prime is 21610609. The next prime is 21610643. The reversal of 21610618 is 81601612.

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., 12411529 + 9199089 = 3523^2 + 3033^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21610592 and 21610601.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5402653 + ... + 5402656.

Almost surely, 2^21610618 is an apocalyptic number.

21610618 is a deficient number, since it is larger than the sum of its proper divisors (10805312).

21610618 is a wasteful number, since it uses less digits than its factorization.

21610618 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10805311.

The product of its (nonzero) digits is 576, while the sum is 25.

The square root of 21610618 is about 4648.7221900217. The cubic root of 21610618 is about 278.5409562360.

The spelling of 21610618 in words is "twenty-one million, six hundred ten thousand, six hundred eighteen".