861025291 has 16 divisors (see below), whose sum is σ = 1014451200. Its totient is φ = 715549248.

The previous prime is 861025271. The next prime is 861025331. The reversal of 861025291 is 192520168.

861025291 = 134² + 135² + ... + 1372².

It is a cyclic number.

It is not a de Polignac number, because 861025291 - 2⁵ = 861025259 is a prime.

It is not an unprimeable number, because it can be changed into a prime (861025201) 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 15 ways as a sum of consecutive naturals, for example, 15870 + ... + 44428.

It is an arithmetic number, because the mean of its divisors is an integer number (63403200).

Almost surely, 2^861025291 is an apocalyptic number.

861025291 is a deficient number, since it is larger than the sum of its proper divisors (153425909).

861025291 is a wasteful number, since it uses less digits than its factorization.

861025291 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28698.

The product of its (nonzero) digits is 8640, while the sum is 34.

The square root of 861025291 is about 29343.2324565648. The cubic root of 861025291 is about 951.3463057518.

The spelling of 861025291 in words is "eight hundred sixty-one million, twenty-five thousand, two hundred ninety-one".