861378761 has 2 divisors, whose sum is σ = 861378762. Its totient is φ = 861378760.

The previous prime is 861378751. The next prime is 861378769. The reversal of 861378761 is 167873168.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 546671161 + 314707600 = 23381^2 + 17740^2 .

It is a cyclic number.

It is not a de Polignac number, because 861378761 - 2⁶ = 861378697 is a prime.

It is not a weakly prime, because it can be changed into another prime (861378769) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 430689380 + 430689381.

It is an arithmetic number, because the mean of its divisors is an integer number (430689381).

Almost surely, 2^861378761 is an apocalyptic number.

It is an amenable number.

861378761 is a deficient number, since it is larger than the sum of its proper divisors (1).

861378761 is an equidigital number, since it uses as much as digits as its factorization.

861378761 is an evil number, because the sum of its binary digits is even.

The product of its digits is 338688, while the sum is 47.

The square root of 861378761 is about 29349.2548627729. The cubic root of 861378761 is about 951.4764708689.

The spelling of 861378761 in words is "eight hundred sixty-one million, three hundred seventy-eight thousand, seven hundred sixty-one".