21610915499 has 4 divisors (see below), whose sum is σ = 21613902336. Its totient is φ = 21607928664.

The previous prime is 21610915481. The next prime is 21610915531. The reversal of 21610915499 is 99451901612.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21610915499 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21610915399) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1482539 + ... + 1497044.

It is an arithmetic number, because the mean of its divisors is an integer number (5403475584).

Almost surely, 2^21610915499 is an apocalyptic number.

21610915499 is a deficient number, since it is larger than the sum of its proper divisors (2986837).

21610915499 is an equidigital number, since it uses as much as digits as its factorization.

21610915499 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2986836.

The product of its (nonzero) digits is 174960, while the sum is 47.

The spelling of 21610915499 in words is "twenty-one billion, six hundred ten million, nine hundred fifteen thousand, four hundred ninety-nine".