3161221891 has 2 divisors, whose sum is σ = 3161221892. Its totient is φ = 3161221890.

The previous prime is 3161221813. The next prime is 3161221979. The reversal of 3161221891 is 1981221613.

3161221891 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-3161221891 is a prime.

It is not a weakly prime, because it can be changed into another prime (3161225891) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1580610945 + 1580610946.

It is an arithmetic number, because the mean of its divisors is an integer number (1580610946).

Almost surely, 2^3161221891 is an apocalyptic number.

3161221891 is a deficient number, since it is larger than the sum of its proper divisors (1).

3161221891 is an equidigital number, since it uses as much as digits as its factorization.

3161221891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5184, while the sum is 34.

The square root of 3161221891 is about 56224.7444725185. The cubic root of 3161221891 is about 1467.6359012273.

The spelling of 3161221891 in words is "three billion, one hundred sixty-one million, two hundred twenty-one thousand, eight hundred ninety-one".