1918739197 has 4 divisors (see below), whose sum is σ = 1965537756. Its totient is φ = 1871940640.

The previous prime is 1918739171. The next prime is 1918739213. The reversal of 1918739197 is 7919378191.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7919378191 = 59 ⋅134226749.

It can be written as a sum of positive squares in 2 ways, for example, as 170328601 + 1748410596 = 13051^2 + 41814^2 .

It is a cyclic number.

It is not a de Polignac number, because 1918739197 - 2¹⁵ = 1918706429 is a prime.

It is a super-2 number, since 2×1918739197² = 7363120212208409618, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1918739107) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 23399218 + ... + 23399299.

It is an arithmetic number, because the mean of its divisors is an integer number (491384439).

Almost surely, 2^1918739197 is an apocalyptic number.

It is an amenable number.

1918739197 is a deficient number, since it is larger than the sum of its proper divisors (46798559).

1918739197 is an equidigital number, since it uses as much as digits as its factorization.

1918739197 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46798558.

The product of its digits is 857304, while the sum is 55.

The square root of 1918739197 is about 43803.4153577093. The cubic root of 1918739197 is about 1242.6208866940.

The spelling of 1918739197 in words is "one billion, nine hundred eighteen million, seven hundred thirty-nine thousand, one hundred ninety-seven".