861921917287 has 8 divisors (see below), whose sum is σ = 899418895200. Its totient is φ = 824426782080.

The previous prime is 861921917281. The next prime is 861921917309. The reversal of 861921917287 is 782719129168.

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

It is a cyclic number.

It is not a de Polignac number, because 861921917287 - 2¹⁹ = 861921392999 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 (861921917281) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 541587 + ... + 1420267.

It is an arithmetic number, because the mean of its divisors is an integer number (112427361900).

Almost surely, 2^861921917287 is an apocalyptic number.

861921917287 is a deficient number, since it is larger than the sum of its proper divisors (37496977913).

861921917287 is a wasteful number, since it uses less digits than its factorization.

861921917287 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 921353.

The product of its digits is 6096384, while the sum is 61.

The spelling of 861921917287 in words is "eight hundred sixty-one billion, nine hundred twenty-one million, nine hundred seventeen thousand, two hundred eighty-seven".