861706551 has 16 divisors (see below), whose sum is σ = 1189929600. Its totient is φ = 554023008.

The previous prime is 861706543. The next prime is 861706567. The reversal of 861706551 is 155607168.

It is not a de Polignac number, because 861706551 - 2³ = 861706543 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861706501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 77160 + ... + 87618.

It is an arithmetic number, because the mean of its divisors is an integer number (74370600).

Almost surely, 2^861706551 is an apocalyptic number.

861706551 is a deficient number, since it is larger than the sum of its proper divisors (328223049).

861706551 is a wasteful number, since it uses less digits than its factorization.

861706551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11438.

The product of its (nonzero) digits is 50400, while the sum is 39.

The square root of 861706551 is about 29354.8386301134. The cubic root of 861706551 is about 951.5971475225.

The spelling of 861706551 in words is "eight hundred sixty-one million, seven hundred six thousand, five hundred fifty-one".