21487699 has 2 divisors, whose sum is σ = 21487700. Its totient is φ = 21487698.

The previous prime is 21487693. The next prime is 21487709. The reversal of 21487699 is 99678412.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21487699 - 2⁵ = 21487667 is a prime.

It is not a weakly prime, because it can be changed into another prime (21487693) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10743849 + 10743850.

It is an arithmetic number, because the mean of its divisors is an integer number (10743850).

Almost surely, 2^21487699 is an apocalyptic number.

21487699 is a deficient number, since it is larger than the sum of its proper divisors (1).

21487699 is an equidigital number, since it uses as much as digits as its factorization.

21487699 is an evil number, because the sum of its binary digits is even.

The product of its digits is 217728, while the sum is 46.

The square root of 21487699 is about 4635.4826070216. The cubic root of 21487699 is about 278.0118475706.

The spelling of 21487699 in words is "twenty-one million, four hundred eighty-seven thousand, six hundred ninety-nine".