861616291 has 4 divisors (see below), whose sum is σ = 866376784. Its totient is φ = 856855800.

The previous prime is 861616289. The next prime is 861616297. The reversal of 861616291 is 192616168.

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

It is a cyclic number.

It is not a de Polignac number, because 861616291 - 2¹ = 861616289 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (861616297) 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, 2379975 + ... + 2380336.

It is an arithmetic number, because the mean of its divisors is an integer number (216594196).

Almost surely, 2^861616291 is an apocalyptic number.

861616291 is a deficient number, since it is larger than the sum of its proper divisors (4760493).

861616291 is a wasteful number, since it uses less digits than its factorization.

861616291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4760492.

The product of its digits is 31104, while the sum is 40.

The square root of 861616291 is about 29353.3011942439. The cubic root of 861616291 is about 951.5639211465.

The spelling of 861616291 in words is "eight hundred sixty-one million, six hundred sixteen thousand, two hundred ninety-one".