21692018 has 4 divisors (see below), whose sum is σ = 32538030. Its totient is φ = 10846008.

The previous prime is 21691979. The next prime is 21692063. The reversal of 21692018 is 81029612.

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., 20912329 + 779689 = 4573^2 + 883^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5423003 + ... + 5423006.

Almost surely, 2^21692018 is an apocalyptic number.

21692018 is a deficient number, since it is larger than the sum of its proper divisors (10846012).

21692018 is a wasteful number, since it uses less digits than its factorization.

21692018 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10846011.

The product of its (nonzero) digits is 1728, while the sum is 29.

The square root of 21692018 is about 4657.4690551844. The cubic root of 21692018 is about 278.8902417239.

The spelling of 21692018 in words is "twenty-one million, six hundred ninety-two thousand, eighteen".