861387280 has 160 divisors (see below), whose sum is σ = 2315101824. Its totient is φ = 295231488.

The previous prime is 861387119. The next prime is 861387281. The reversal of 861387280 is 82783168.

It is a happy number.

861387280 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×861387280² = 1483976092291596800, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (861387281) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1467147 + ... + 1467733.

Almost surely, 2^861387280 is an apocalyptic number.

861387280 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 861387280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1157550912).

861387280 is an abundant number, since it is smaller than the sum of its proper divisors (1453714544).

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

861387280 is a wasteful number, since it uses less digits than its factorization.

861387280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 713 (or 707 counting only the distinct ones).

The product of its (nonzero) digits is 129024, while the sum is 43.

The square root of 861387280 is about 29349.3999938670. The cubic root of 861387280 is about 951.4796075461.

The spelling of 861387280 in words is "eight hundred sixty-one million, three hundred eighty-seven thousand, two hundred eighty".