8613721800 has 72 divisors (see below), whose sum is σ = 28927755090. Its totient is φ = 2296992000.

The previous prime is 8613721777. The next prime is 8613721807. The reversal of 8613721800 is 81273168.

It can be written as a sum of positive squares in 3 ways, for example, as 7788768516 + 824953284 = 88254^2 + 28722^2 .

It is a tau number, because it is divible by the number of its divisors (72).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (8613721807) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 2390901 + ... + 2394500.

Almost surely, 2^8613721800 is an apocalyptic number.

It is an amenable number.

8613721800 is an abundant number, since it is smaller than the sum of its proper divisors (20314033290).

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

8613721800 is a wasteful number, since it uses less digits than its factorization.

8613721800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4785423 (or 4785411 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 36.

The square root of 8613721800 is about 92810.1384548046. The cubic root of 8613721800 is about 2049.8886951267. Note that the first 3 decimals are identical.

Adding to 8613721800 its reverse (81273168), we get a palindrome (8694994968).

The spelling of 8613721800 in words is "eight billion, six hundred thirteen million, seven hundred twenty-one thousand, eight hundred".