39121891 has 2 divisors, whose sum is σ = 39121892. Its totient is φ = 39121890.

The previous prime is 39121877. The next prime is 39121909. The reversal of 39121891 is 19812193.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 39121891 - 2⁷ = 39121763 is a prime.

It is not a weakly prime, because it can be changed into another prime (39121871) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19560945 + 19560946.

It is an arithmetic number, because the mean of its divisors is an integer number (19560946).

Almost surely, 2^39121891 is an apocalyptic number.

39121891 is a deficient number, since it is larger than the sum of its proper divisors (1).

39121891 is an equidigital number, since it uses as much as digits as its factorization.

39121891 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3888, while the sum is 34.

The square root of 39121891 is about 6254.7494753987. The cubic root of 39121891 is about 339.4740744401.

The spelling of 39121891 in words is "thirty-nine million, one hundred twenty-one thousand, eight hundred ninety-one".