21868459 has 2 divisors, whose sum is σ = 21868460. Its totient is φ = 21868458.

The previous prime is 21868447. The next prime is 21868471. The reversal of 21868459 is 95486812.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (21868447) and next prime (21868471).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21868459 is a prime.

It is not a weakly prime, because it can be changed into another prime (21860459) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10934229 + 10934230.

It is an arithmetic number, because the mean of its divisors is an integer number (10934230).

Almost surely, 2^21868459 is an apocalyptic number.

21868459 is a deficient number, since it is larger than the sum of its proper divisors (1).

21868459 is an equidigital number, since it uses as much as digits as its factorization.

21868459 is an evil number, because the sum of its binary digits is even.

The product of its digits is 138240, while the sum is 43.

The square root of 21868459 is about 4676.3724188734. The cubic root of 21868459 is about 279.6443571439.

The spelling of 21868459 in words is "twenty-one million, eight hundred sixty-eight thousand, four hundred fifty-nine".