861378786 has 20 divisors (see below), whose sum is σ = 1930126902. Its totient is φ = 287126208.

The previous prime is 861378781. The next prime is 861378787. The reversal of 861378786 is 687873168.

It can be written as a sum of positive squares in only one way, i.e., 860307561 + 1071225 = 29331^2 + 1035^2 .

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (861378781) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 2658415 + ... + 2658738.

Almost surely, 2^861378786 is an apocalyptic number.

861378786 is an abundant number, since it is smaller than the sum of its proper divisors (1068748116).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

861378786 is a wasteful number, since it uses less digits than its factorization.

861378786 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5317167 (or 5317158 counting only the distinct ones).

The product of its digits is 2709504, while the sum is 54.

The square root of 861378786 is about 29349.2552886781. The cubic root of 861378786 is about 951.4764800739.

The spelling of 861378786 in words is "eight hundred sixty-one million, three hundred seventy-eight thousand, seven hundred eighty-six".