21769818317 has 18 divisors (see below), whose sum is σ = 24033429162. Its totient is φ = 19703415264.

The previous prime is 21769818313. The next prime is 21769818319. The reversal of 21769818317 is 71381896712.

It can be written as a sum of positive squares in 3 ways, for example, as 294088201 + 21475730116 = 17149^2 + 146546^2 .

It is not a de Polignac number, because 21769818317 - 2² = 21769818313 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (53).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21769818313) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 13963184 + ... + 13964742.

It is an arithmetic number, because the mean of its divisors is an integer number (1335190509).

Almost surely, 2^21769818317 is an apocalyptic number.

It is an amenable number.

21769818317 is a deficient number, since it is larger than the sum of its proper divisors (2263610845).

21769818317 is an frugal number, since it uses more digits than its factorization.

21769818317 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3197 (or 1625 counting only the distinct ones).

The product of its digits is 1016064, while the sum is 53.

Multiplying 21769818317 by its sum of digits (53), we get a square (1153800370801 = 1074151²).

21769818317 divided by its sum of digits (53) gives a square (410751289 = 20267²).

The spelling of 21769818317 in words is "twenty-one billion, seven hundred sixty-nine million, eight hundred eighteen thousand, three hundred seventeen".