721138418 has 64 divisors (see below), whose sum is σ = 1502565120. Its totient is φ = 250387200.

The previous prime is 721138417. The next prime is 721138433. The reversal of 721138418 is 814831127.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (721138417) 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 31 ways as a sum of consecutive naturals, for example, 51848 + ... + 64268.

It is an arithmetic number, because the mean of its divisors is an integer number (23477580).

Almost surely, 2^721138418 is an apocalyptic number.

721138418 is an abundant number, since it is smaller than the sum of its proper divisors (781426702).

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

721138418 is a wasteful number, since it uses less digits than its factorization.

721138418 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12483.

The product of its digits is 10752, while the sum is 35.

The square root of 721138418 is about 26854.0205183507. The cubic root of 721138418 is about 896.7530812887.

The spelling of 721138418 in words is "seven hundred twenty-one million, one hundred thirty-eight thousand, four hundred eighteen".