18191161402 has 4 divisors (see below), whose sum is σ = 27286742106. Its totient is φ = 9095580700.

The previous prime is 18191161399. The next prime is 18191161517. The reversal of 18191161402 is 20416119181.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 20416119181 = 967 ⋅21112843.

It can be written as a sum of positive squares in only one way, i.e., 18182095281 + 9066121 = 134841^2 + 3011^2 .

It is a super-2 number, since 2×18191161402² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4547790349 + ... + 4547790352.

Almost surely, 2^18191161402 is an apocalyptic number.

18191161402 is a deficient number, since it is larger than the sum of its proper divisors (9095580704).

18191161402 is an equidigital number, since it uses as much as digits as its factorization.

18191161402 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9095580703.

The product of its (nonzero) digits is 3456, while the sum is 34.

The spelling of 18191161402 in words is "eighteen billion, one hundred ninety-one million, one hundred sixty-one thousand, four hundred two".