21017990049 has 16 divisors (see below), whose sum is σ = 33060556800. Its totient is φ = 11622851280.

The previous prime is 21017990047. The next prime is 21017990083. The reversal of 21017990049 is 94009971012.

It is not a de Polignac number, because 21017990049 - 2¹ = 21017990047 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21017990041) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16142199 + ... + 16143500.

It is an arithmetic number, because the mean of its divisors is an integer number (2066284800).

Almost surely, 2^21017990049 is an apocalyptic number.

It is an amenable number.

21017990049 is a deficient number, since it is larger than the sum of its proper divisors (12042566751).

21017990049 is a wasteful number, since it uses less digits than its factorization.

21017990049 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32285740.

The product of its (nonzero) digits is 40824, while the sum is 42.

The spelling of 21017990049 in words is "twenty-one billion, seventeen million, nine hundred ninety thousand, forty-nine".