861863280 has 80 divisors (see below), whose sum is σ = 2828952864. Its totient is φ = 216309760.

The previous prime is 861863269. The next prime is 861863281. The reversal of 861863280 is 82368168.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861863281) 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 15 ways as a sum of consecutive naturals, for example, 101541 + ... + 109700.

Almost surely, 2^861863280 is an apocalyptic number.

861863280 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

861863280 is an abundant number, since it is smaller than the sum of its proper divisors (1967089584).

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

861863280 is a wasteful number, since it uses less digits than its factorization.

861863280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 211274 (or 211268 counting only the distinct ones).

The product of its (nonzero) digits is 110592, while the sum is 42.

The square root of 861863280 is about 29357.5080686355. The cubic root of 861863280 is about 951.6548368554.

The spelling of 861863280 in words is "eight hundred sixty-one million, eight hundred sixty-three thousand, two hundred eighty".