861991015 has 8 divisors (see below), whose sum is σ = 1035091008. Its totient is φ = 689124960.

The previous prime is 861990973. The next prime is 861991021. The reversal of 861991015 is 510199168.

861991015 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 861991015 - 2²¹ = 859893863 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 50271 + ... + 65200.

It is an arithmetic number, because the mean of its divisors is an integer number (129386376).

Almost surely, 2^861991015 is an apocalyptic number.

861991015 is a deficient number, since it is larger than the sum of its proper divisors (173099993).

861991015 is a wasteful number, since it uses less digits than its factorization.

861991015 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 116969.

The product of its (nonzero) digits is 19440, while the sum is 40.

The square root of 861991015 is about 29359.6834962504. The cubic root of 861991015 is about 951.7018488075.

The spelling of 861991015 in words is "eight hundred sixty-one million, nine hundred ninety-one thousand, fifteen".