139869991 has 2 divisors, whose sum is σ = 139869992. Its totient is φ = 139869990.

The previous prime is 139869911. The next prime is 139870009. The reversal of 139869991 is 199968931.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-139869991 is a prime.

It is a super-2 number, since 2×139869991² = 39127228764680162, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (139869911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69934995 + 69934996.

It is an arithmetic number, because the mean of its divisors is an integer number (69934996).

Almost surely, 2^139869991 is an apocalyptic number.

139869991 is a deficient number, since it is larger than the sum of its proper divisors (1).

139869991 is an equidigital number, since it uses as much as digits as its factorization.

139869991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 944784, while the sum is 55.

The square root of 139869991 is about 11826.6644071775. The cubic root of 139869991 is about 519.0886292235.

The spelling of 139869991 in words is "one hundred thirty-nine million, eight hundred sixty-nine thousand, nine hundred ninety-one".