1791917989 has 4 divisors (see below), whose sum is σ = 1792003500. Its totient is φ = 1791832480.

The previous prime is 1791917977. The next prime is 1791917999. The reversal of 1791917989 is 9897191971.

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 2 ways, for example, as 1053002500 + 738915489 = 32450^2 + 27183^2 .

It is a cyclic number.

It is not a de Polignac number, because 1791917989 - 2¹¹ = 1791915941 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1791917909) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12369 + ... + 61129.

It is an arithmetic number, because the mean of its divisors is an integer number (448000875).

Almost surely, 2^1791917989 is an apocalyptic number.

It is an amenable number.

1791917989 is a deficient number, since it is larger than the sum of its proper divisors (85511).

1791917989 is an equidigital number, since it uses as much as digits as its factorization.

1791917989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85510.

The product of its digits is 2571912, while the sum is 61.

The square root of 1791917989 is about 42331.0523020631. The cubic root of 1791917989 is about 1214.6170591746.

The spelling of 1791917989 in words is "one billion, seven hundred ninety-one million, nine hundred seventeen thousand, nine hundred eighty-nine".