861188720 has 120 divisors (see below), whose sum is σ = 2466364464. Its totient is φ = 277874688.

The previous prime is 861188681. The next prime is 861188761. The reversal of 861188720 is 27881168.

It is a super-2 number, since 2×861188720² = 1483292022910476800, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 60179 + ... + 73101.

Almost surely, 2^861188720 is an apocalyptic number.

861188720 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 861188720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1233182232).

861188720 is an abundant number, since it is smaller than the sum of its proper divisors (1605175744).

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

861188720 is a wasteful number, since it uses less digits than its factorization.

861188720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12967 (or 12954 counting only the distinct ones).

The product of its (nonzero) digits is 43008, while the sum is 41.

The square root of 861188720 is about 29346.0171062446. The cubic root of 861188720 is about 951.4064928107.

The spelling of 861188720 in words is "eight hundred sixty-one million, one hundred eighty-eight thousand, seven hundred twenty".