1918156397 has 2 divisors, whose sum is σ = 1918156398. Its totient is φ = 1918156396.

The previous prime is 1918156379. The next prime is 1918156399. The reversal of 1918156397 is 7936518191.

Together with previous prime (1918156379) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1841611396 + 76545001 = 42914^2 + 8749^2 .

It is a cyclic number.

It is not a de Polignac number, because 1918156397 - 2¹⁶ = 1918090861 is a prime.

Together with 1918156399, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1918156399) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 959078198 + 959078199.

It is an arithmetic number, because the mean of its divisors is an integer number (959078199).

Almost surely, 2^1918156397 is an apocalyptic number.

It is an amenable number.

1918156397 is a deficient number, since it is larger than the sum of its proper divisors (1).

1918156397 is an equidigital number, since it uses as much as digits as its factorization.

1918156397 is an evil number, because the sum of its binary digits is even.

The product of its digits is 408240, while the sum is 50.

The square root of 1918156397 is about 43796.7624031731. The cubic root of 1918156397 is about 1242.4950622656.

The spelling of 1918156397 in words is "one billion, nine hundred eighteen million, one hundred fifty-six thousand, three hundred ninety-seven".