861999445 has 4 divisors (see below), whose sum is σ = 1034399340. Its totient is φ = 689599552.

The previous prime is 861999431. The next prime is 861999449. The reversal of 861999445 is 544999168.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 576288036 + 285711409 = 24006^2 + 16903^2 .

It is a cyclic number.

It is not a de Polignac number, because 861999445 - 2²¹ = 859902293 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861999449) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 86199940 + ... + 86199949.

It is an arithmetic number, because the mean of its divisors is an integer number (258599835).

Almost surely, 2^861999445 is an apocalyptic number.

It is an amenable number.

861999445 is a deficient number, since it is larger than the sum of its proper divisors (172399895).

861999445 is a wasteful number, since it uses less digits than its factorization.

861999445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 172399894.

The product of its digits is 2799360, while the sum is 55.

The square root of 861999445 is about 29359.8270601174. The cubic root of 861999445 is about 951.7049512452.

The spelling of 861999445 in words is "eight hundred sixty-one million, nine hundred ninety-nine thousand, four hundred forty-five".