861362991 has 20 divisors (see below), whose sum is σ = 1303024800. Its totient is φ = 566968896.

The previous prime is 861362927. The next prime is 861363001. The reversal of 861362991 is 199263168.

It is a happy number.

861362991 is a `hidden beast` number, since 8 + 6 + 13 + 629 + 9 + 1 = 666.

It is not a de Polignac number, because 861362991 - 2⁶ = 861362927 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861362911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 60906 + ... + 73703.

It is an arithmetic number, because the mean of its divisors is an integer number (65151240).

Almost surely, 2^861362991 is an apocalyptic number.

861362991 is a gapful number since it is divisible by the number (81) formed by its first and last digit.

861362991 is a deficient number, since it is larger than the sum of its proper divisors (441661809).

861362991 is a wasteful number, since it uses less digits than its factorization.

861362991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 134700 (or 134691 counting only the distinct ones).

The product of its digits is 139968, while the sum is 45.

The square root of 861362991 is about 29348.9862005487. The cubic root of 861362991 is about 951.4706643348.

The spelling of 861362991 in words is "eight hundred sixty-one million, three hundred sixty-two thousand, nine hundred ninety-one".