861321745 has 16 divisors (see below), whose sum is σ = 1095074640. Its totient is φ = 648116224.

The previous prime is 861321731. The next prime is 861321749. The reversal of 861321745 is 547123168.

861321745 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 8 ways, for example, as 16641 + 861305104 = 129^2 + 29348^2 .

It is a cyclic number.

It is not a de Polignac number, because 861321745 - 2²⁵ = 827767313 is a prime.

It is not an unprimeable number, because it can be changed into a prime (861321749) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 250659 + ... + 254071.

It is an arithmetic number, because the mean of its divisors is an integer number (68442165).

Almost surely, 2^861321745 is an apocalyptic number.

861321745 is a gapful number since it is divisible by the number (85) formed by its first and last digit.

It is an amenable number.

861321745 is a deficient number, since it is larger than the sum of its proper divisors (233752895).

861321745 is a wasteful number, since it uses less digits than its factorization.

861321745 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6404.

The product of its digits is 40320, while the sum is 37.

The square root of 861321745 is about 29348.2835102839. The cubic root of 861321745 is about 951.4554771699.

The spelling of 861321745 in words is "eight hundred sixty-one million, three hundred twenty-one thousand, seven hundred forty-five".