311780891 has 2 divisors, whose sum is σ = 311780892. Its totient is φ = 311780890.

The previous prime is 311780881. The next prime is 311780923. The reversal of 311780891 is 198087113.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 311780891 - 2¹⁸ = 311518747 is a prime.

It is not a weakly prime, because it can be changed into another prime (311780881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 155890445 + 155890446.

It is an arithmetic number, because the mean of its divisors is an integer number (155890446).

Almost surely, 2^311780891 is an apocalyptic number.

311780891 is a deficient number, since it is larger than the sum of its proper divisors (1).

311780891 is an equidigital number, since it uses as much as digits as its factorization.

311780891 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12096, while the sum is 38.

The square root of 311780891 is about 17657.3183411298. The cubic root of 311780891 is about 678.0834811336.

The spelling of 311780891 in words is "three hundred eleven million, seven hundred eighty thousand, eight hundred ninety-one".