21798878969 has 8 divisors (see below), whose sum is σ = 25421433600. Its totient is φ = 18684753108.

The previous prime is 21798878957. The next prime is 21798878977. The reversal of 21798878969 is 96987889712.

It is not a de Polignac number, because 21798878969 - 2⁸ = 21798878713 is a prime.

It is a super-2 number, since 2×21798878969² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21798878896 and 21798878905.

It is not an unprimeable number, because it can be changed into a prime (21798878909) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 31776449 + ... + 31777134.

It is an arithmetic number, because the mean of its divisors is an integer number (3177679200).

Almost surely, 2^21798878969 is an apocalyptic number.

It is an amenable number.

21798878969 is a deficient number, since it is larger than the sum of its proper divisors (3622554631).

21798878969 is an frugal number, since it uses more digits than its factorization.

21798878969 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63553604 (or 63553590 counting only the distinct ones).

The product of its digits is 219469824, while the sum is 74.

The spelling of 21798878969 in words is "twenty-one billion, seven hundred ninety-eight million, eight hundred seventy-eight thousand, nine hundred sixty-nine".