865772720 has 40 divisors (see below), whose sum is σ = 2021388480. Its totient is φ = 344852480.

The previous prime is 865772689. The next prime is 865772729. The reversal of 865772720 is 27277568.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (40).

It is not an unprimeable number, because it can be changed into a prime (865772729) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3521 + ... + 41760.

It is an arithmetic number, because the mean of its divisors is an integer number (50534712).

Almost surely, 2^865772720 is an apocalyptic number.

865772720 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

865772720 is an abundant number, since it is smaller than the sum of its proper divisors (1155615760).

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

865772720 is a wasteful number, since it uses less digits than its factorization.

865772720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45533 (or 45527 counting only the distinct ones).

The product of its (nonzero) digits is 329280, while the sum is 44.

The square root of 865772720 is about 29424.0160413224. The cubic root of 865772720 is about 953.0915791488.

The spelling of 865772720 in words is "eight hundred sixty-five million, seven hundred seventy-two thousand, seven hundred twenty".