18390885769 has 3 divisors (see below), whose sum is σ = 18391021383. Its totient is φ = 18390750156.

The previous prime is 18390885763. The next prime is 18390885803. The reversal of 18390885769 is 96758809381.

The square root of 18390885769 is 135613.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 16364805625 + 2026080144 = 127925^2 + 45012^2 .

It is not a de Polignac number, because 18390885769 - 2¹⁵ = 18390853001 is a prime.

It is a super-2 number, since 2×18390885769² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18390885769.

It is not an unprimeable number, because it can be changed into a prime (18390885763) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 67807 + ... + 203419.

It is an arithmetic number, because the mean of its divisors is an integer number (6130340461).

Almost surely, 2^18390885769 is an apocalyptic number.

18390885769 is the 135613-rd square number.

18390885769 is the 67807-th centered octagonal number.

It is an amenable number.

18390885769 is a deficient number, since it is larger than the sum of its proper divisors (135614).

18390885769 is an frugal number, since it uses more digits than its factorization.

18390885769 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 271226 (or 135613 counting only the distinct ones).

The product of its (nonzero) digits is 26127360, while the sum is 64.

Multiplying 18390885769 by its sum of digits (64), we get a square (1177016689216 = 1084904²).

The spelling of 18390885769 in words is "eighteen billion, three hundred ninety million, eight hundred eighty-five thousand, seven hundred sixty-nine".