2138891197 has 2 divisors, whose sum is σ = 2138891198. Its totient is φ = 2138891196.

The previous prime is 2138891191. The next prime is 2138891219. The reversal of 2138891197 is 7911988312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2019513721 + 119377476 = 44939^2 + 10926^2 .

It is a cyclic number.

It is not a de Polignac number, because 2138891197 - 2¹⁵ = 2138858429 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 2138891197.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2138891191) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1069445598 + 1069445599.

It is an arithmetic number, because the mean of its divisors is an integer number (1069445599).

Almost surely, 2^2138891197 is an apocalyptic number.

It is an amenable number.

2138891197 is a deficient number, since it is larger than the sum of its proper divisors (1).

2138891197 is an equidigital number, since it uses as much as digits as its factorization.

2138891197 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 217728, while the sum is 49.

The square root of 2138891197 is about 46248.1480385972. The cubic root of 2138891197 is about 1288.4361388767.

The spelling of 2138891197 in words is "two billion, one hundred thirty-eight million, eight hundred ninety-one thousand, one hundred ninety-seven".