21718363 has 2 divisors, whose sum is σ = 21718364. Its totient is φ = 21718362.

The previous prime is 21718351. The next prime is 21718369. The reversal of 21718363 is 36381712.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21718363 is a prime.

It is not a weakly prime, because it can be changed into another prime (21718369) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10859181 + 10859182.

It is an arithmetic number, because the mean of its divisors is an integer number (10859182).

Almost surely, 2^21718363 is an apocalyptic number.

21718363 is a deficient number, since it is larger than the sum of its proper divisors (1).

21718363 is an equidigital number, since it uses as much as digits as its factorization.

21718363 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6048, while the sum is 31.

The square root of 21718363 is about 4660.2964497980. The cubic root of 21718363 is about 279.0031003026.

The spelling of 21718363 in words is "twenty-one million, seven hundred eighteen thousand, three hundred sixty-three".