861611389 has 4 divisors (see below), whose sum is σ = 864329724. Its totient is φ = 858893056.

The previous prime is 861611353. The next prime is 861611393. The reversal of 861611389 is 983116168.

It is a happy number.

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 106296100 + 755315289 = 10310^2 + 27483^2 .

It is a cyclic number.

It is not a de Polignac number, because 861611389 - 2¹¹ = 861609341 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861615389) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1358692 + ... + 1359325.

It is an arithmetic number, because the mean of its divisors is an integer number (216082431).

Almost surely, 2^861611389 is an apocalyptic number.

It is an amenable number.

861611389 is a deficient number, since it is larger than the sum of its proper divisors (2718335).

861611389 is a wasteful number, since it uses less digits than its factorization.

861611389 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2718334.

The product of its digits is 62208, while the sum is 43.

The square root of 861611389 is about 29353.2176941473. The cubic root of 861611389 is about 951.5621165632.

The spelling of 861611389 in words is "eight hundred sixty-one million, six hundred eleven thousand, three hundred eighty-nine".