2151172861 has 2 divisors, whose sum is σ = 2151172862. Its totient is φ = 2151172860.

The previous prime is 2151172853. The next prime is 2151172867. The reversal of 2151172861 is 1682711512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2136195961 + 14976900 = 46219^2 + 3870^2 .

It is a cyclic number.

It is not a de Polignac number, because 2151172861 - 2³ = 2151172853 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2151172867) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1075586430 + 1075586431.

It is an arithmetic number, because the mean of its divisors is an integer number (1075586431).

Almost surely, 2^2151172861 is an apocalyptic number.

It is an amenable number.

2151172861 is a deficient number, since it is larger than the sum of its proper divisors (1).

2151172861 is an equidigital number, since it uses as much as digits as its factorization.

2151172861 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6720, while the sum is 34.

The square root of 2151172861 is about 46380.7380385435. The cubic root of 2151172861 is about 1290.8975307482.

The spelling of 2151172861 in words is "two billion, one hundred fifty-one million, one hundred seventy-two thousand, eight hundred sixty-one".