21718366 has 4 divisors (see below), whose sum is σ = 32577552. Its totient is φ = 10859182.

The previous prime is 21718363. The next prime is 21718369. The reversal of 21718366 is 66381712.

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

It is an interprime number because it is at equal distance from previous prime (21718363) and next prime (21718369).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21718363) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5429590 + ... + 5429593.

It is an arithmetic number, because the mean of its divisors is an integer number (8144388).

Almost surely, 2^21718366 is an apocalyptic number.

21718366 is a deficient number, since it is larger than the sum of its proper divisors (10859186).

21718366 is a wasteful number, since it uses less digits than its factorization.

21718366 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10859185.

The product of its digits is 12096, while the sum is 34.

The square root of 21718366 is about 4660.2967716659. The cubic root of 21718366 is about 279.0031131490.

The spelling of 21718366 in words is "twenty-one million, seven hundred eighteen thousand, three hundred sixty-six".