18694381690 has 12 divisors (see below), whose sum is σ = 33650665326. Its totient is φ = 7477579728.

The previous prime is 18694381681. The next prime is 18694381691. The reversal of 18694381690 is 9618349681.

It can be written as a sum of positive squares in 3 ways, for example, as 4171480569 + 14522901121 = 64587^2 + 120511^2 .

It is a super-2 number, since 2×18694381690² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (18694381691) 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, 410752 + ... + 453988.

Almost surely, 2^18694381690 is an apocalyptic number.

18694381690 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

18694381690 is a deficient number, since it is larger than the sum of its proper divisors (14956283636).

18694381690 is an frugal number, since it uses more digits than its factorization.

18694381690 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 86481 (or 43244 counting only the distinct ones).

The product of its (nonzero) digits is 2239488, while the sum is 55.

The spelling of 18694381690 in words is "eighteen billion, six hundred ninety-four million, three hundred eighty-one thousand, six hundred ninety".