2156357261 has 2 divisors, whose sum is σ = 2156357262. Its totient is φ = 2156357260.

The previous prime is 2156357209. The next prime is 2156357267. The reversal of 2156357261 is 1627536512.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1926683236 + 229674025 = 43894^2 + 15155^2 .

It is a cyclic number.

It is not a de Polignac number, because 2156357261 - 2²⁶ = 2089248397 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2156357267) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1078178630 + 1078178631.

It is an arithmetic number, because the mean of its divisors is an integer number (1078178631).

Almost surely, 2^2156357261 is an apocalyptic number.

It is an amenable number.

2156357261 is a deficient number, since it is larger than the sum of its proper divisors (1).

2156357261 is an equidigital number, since it uses as much as digits as its factorization.

2156357261 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 75600, while the sum is 38.

The square root of 2156357261 is about 46436.5939857781. The cubic root of 2156357261 is about 1291.9337344643.

The spelling of 2156357261 in words is "two billion, one hundred fifty-six million, three hundred fifty-seven thousand, two hundred sixty-one".