21602018 has 4 divisors (see below), whose sum is σ = 32403030. Its totient is φ = 10801008.

The previous prime is 21602003. The next prime is 21602029. The reversal of 21602018 is 81020612.

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., 16507969 + 5094049 = 4063^2 + 2257^2 .

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, 5400503 + ... + 5400506.

Almost surely, 2^21602018 is an apocalyptic number.

21602018 is a deficient number, since it is larger than the sum of its proper divisors (10801012).

21602018 is a wasteful number, since it uses less digits than its factorization.

21602018 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10801011.

The product of its (nonzero) digits is 192, while the sum is 20.

The square root of 21602018 is about 4647.7971126115. The cubic root of 21602018 is about 278.5040026414.

The spelling of 21602018 in words is "twenty-one million, six hundred two thousand, eighteen".