721100018 has 8 divisors (see below), whose sum is σ = 1087626540. Its totient is φ = 358557840.

The previous prime is 721100011. The next prime is 721100053. The reversal of 721100018 is 810001127.

It can be written as a sum of positive squares in 2 ways, for example, as 666827329 + 54272689 = 25823^2 + 7367^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (721100011) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 995633 + ... + 996356.

Almost surely, 2^721100018 is an apocalyptic number.

721100018 is a deficient number, since it is larger than the sum of its proper divisors (366526522).

721100018 is a wasteful number, since it uses less digits than its factorization.

721100018 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1992172.

The product of its (nonzero) digits is 112, while the sum is 20.

The square root of 721100018 is about 26853.3055320942. The cubic root of 721100018 is about 896.7371638963.

The spelling of 721100018 in words is "seven hundred twenty-one million, one hundred thousand, eighteen".