2156949391 has 2 divisors, whose sum is σ = 2156949392. Its totient is φ = 2156949390.

The previous prime is 2156949371. The next prime is 2156949419. The reversal of 2156949391 is 1939496512.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 2156949391 - 2²¹ = 2154852239 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2156949371) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1078474695 + 1078474696.

It is an arithmetic number, because the mean of its divisors is an integer number (1078474696).

Almost surely, 2^2156949391 is an apocalyptic number.

2156949391 is a deficient number, since it is larger than the sum of its proper divisors (1).

2156949391 is an equidigital number, since it uses as much as digits as its factorization.

2156949391 is an evil number, because the sum of its binary digits is even.

The product of its digits is 524880, while the sum is 49.

The square root of 2156949391 is about 46442.9692310903. The cubic root of 2156949391 is about 1292.0519775039.

The spelling of 2156949391 in words is "two billion, one hundred fifty-six million, nine hundred forty-nine thousand, three hundred ninety-one".