861901278 has 24 divisors (see below), whose sum is σ = 2005240392. Its totient is φ = 246257424.

The previous prime is 861901267. The next prime is 861901279. The reversal of 861901278 is 872109168.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861901279) 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 11 ways as a sum of consecutive naturals, for example, 1465525 + ... + 1466112.

It is an arithmetic number, because the mean of its divisors is an integer number (83551683).

Almost surely, 2^861901278 is an apocalyptic number.

861901278 is an abundant number, since it is smaller than the sum of its proper divisors (1143339114).

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

861901278 is a wasteful number, since it uses less digits than its factorization.

861901278 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2931656 (or 2931649 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 42.

The square root of 861901278 is about 29358.1552213350. The cubic root of 861901278 is about 951.6688222325.

The spelling of 861901278 in words is "eight hundred sixty-one million, nine hundred one thousand, two hundred seventy-eight".