2156890237 has 2 divisors, whose sum is σ = 2156890238. Its totient is φ = 2156890236.

The previous prime is 2156890223. The next prime is 2156890273. The reversal of 2156890237 is 7320986512.

Together with next prime (2156890273) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1586349241 + 570540996 = 39829^2 + 23886^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2156890237 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 2156890193 and 2156890202.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2156890217) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1078445118 + 1078445119.

It is an arithmetic number, because the mean of its divisors is an integer number (1078445119).

Almost surely, 2^2156890237 is an apocalyptic number.

It is an amenable number.

2156890237 is a deficient number, since it is larger than the sum of its proper divisors (1).

2156890237 is an equidigital number, since it uses as much as digits as its factorization.

2156890237 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 181440, while the sum is 43.

The square root of 2156890237 is about 46442.3323811369. The cubic root of 2156890237 is about 1292.0401659547.

The spelling of 2156890237 in words is "two billion, one hundred fifty-six million, eight hundred ninety thousand, two hundred thirty-seven".