17781819057 has 8 divisors (see below), whose sum is σ = 26343435680. Its totient is φ = 11854546020.

The previous prime is 17781819053. The next prime is 17781819067. The reversal of 17781819057 is 75091818771.

It is not a de Polignac number, because 17781819057 - 2² = 17781819053 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 17781818994 and 17781819012.

It is not an unprimeable number, because it can be changed into a prime (17781819053) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 329292919 + ... + 329292972.

It is an arithmetic number, because the mean of its divisors is an integer number (3292929460).

Almost surely, 2^17781819057 is an apocalyptic number.

It is an amenable number.

17781819057 is a deficient number, since it is larger than the sum of its proper divisors (8561616623).

17781819057 is an equidigital number, since it uses as much as digits as its factorization.

17781819057 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 658585900 (or 658585894 counting only the distinct ones).

The product of its (nonzero) digits is 987840, while the sum is 54.

The spelling of 17781819057 in words is "seventeen billion, seven hundred eighty-one million, eight hundred nineteen thousand, fifty-seven".