3129991 has 2 divisors, whose sum is σ = 3129992. Its totient is φ = 3129990.

The previous prime is 3129967. The next prime is 3130007. The reversal of 3129991 is 1999213.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 3129991 - 2¹⁵ = 3097223 is a prime.

3129991 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3129911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1564995 + 1564996.

It is an arithmetic number, because the mean of its divisors is an integer number (1564996).

Almost surely, 2^3129991 is an apocalyptic number.

3129991 is a deficient number, since it is larger than the sum of its proper divisors (1).

3129991 is an equidigital number, since it uses as much as digits as its factorization.

3129991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4374, while the sum is 34.

The square root of 3129991 is about 1769.1780577432. The cubic root of 3129991 is about 146.2786789644.

The spelling of 3129991 in words is "three million, one hundred twenty-nine thousand, nine hundred ninety-one".