6138991 has 2 divisors, whose sum is σ = 6138992. Its totient is φ = 6138990.

The previous prime is 6138983. The next prime is 6139019. The reversal of 6138991 is 1998316.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 6138991 - 2³ = 6138983 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 6138991.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6138901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3069495 + 3069496.

It is an arithmetic number, because the mean of its divisors is an integer number (3069496).

Almost surely, 2^6138991 is an apocalyptic number.

6138991 is the 1431-st hex number.

6138991 is a deficient number, since it is larger than the sum of its proper divisors (1).

6138991 is an equidigital number, since it uses as much as digits as its factorization.

6138991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 11664, while the sum is 37.

The square root of 6138991 is about 2477.6987306773. The cubic root of 6138991 is about 183.1044920676.

It can be divided in two parts, 613 and 8991, that added together give a square (9604 = 98²).

The spelling of 6138991 in words is "six million, one hundred thirty-eight thousand, nine hundred ninety-one".