861567780 has 48 divisors (see below), whose sum is σ = 2468499264. Its totient is φ = 224407680.

The previous prime is 861567767. The next prime is 861567799. The reversal of 861567780 is 87765168.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 164391 + ... + 169550.

It is an arithmetic number, because the mean of its divisors is an integer number (51427068).

Almost surely, 2^861567780 is an apocalyptic number.

It is an amenable number.

861567780 is an abundant number, since it is smaller than the sum of its proper divisors (1606931484).

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

861567780 is a wasteful number, since it uses less digits than its factorization.

861567780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 333996 (or 333994 counting only the distinct ones).

The product of its (nonzero) digits is 564480, while the sum is 48.

The square root of 861567780 is about 29352.4748530682. The cubic root of 861567780 is about 951.5460623911.

The spelling of 861567780 in words is "eight hundred sixty-one million, five hundred sixty-seven thousand, seven hundred eighty".