21292318 has 4 divisors (see below), whose sum is σ = 31938480. Its totient is φ = 10646158.

The previous prime is 21292309. The next prime is 21292343. The reversal of 21292318 is 81329212.

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 polite number, since it can be written as a sum of consecutive naturals, namely, 5323078 + ... + 5323081.

It is an arithmetic number, because the mean of its divisors is an integer number (7984620).

Almost surely, 2^21292318 is an apocalyptic number.

21292318 is a deficient number, since it is larger than the sum of its proper divisors (10646162).

21292318 is a wasteful number, since it uses less digits than its factorization.

21292318 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10646161.

The product of its digits is 1728, while the sum is 28.

The square root of 21292318 is about 4614.3599772883. The cubic root of 21292318 is about 277.1666554373.

The spelling of 21292318 in words is "twenty-one million, two hundred ninety-two thousand, three hundred eighteen".