21008210499 has 6 divisors (see below), whose sum is σ = 30345192956. Its totient is φ = 14005473660.

The previous prime is 21008210467. The next prime is 21008210507. The reversal of 21008210499 is 99401280012.

It is not a de Polignac number, because 21008210499 - 2⁵ = 21008210467 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21008210459) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1167122797 + ... + 1167122814.

Almost surely, 2^21008210499 is an apocalyptic number.

21008210499 is a deficient number, since it is larger than the sum of its proper divisors (9336982457).

21008210499 is a wasteful number, since it uses less digits than its factorization.

21008210499 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2334245617 (or 2334245614 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 36.

The spelling of 21008210499 in words is "twenty-one billion, eight million, two hundred ten thousand, four hundred ninety-nine".