721201809816 has 192 divisors, whose sum is σ = 2024196894720. Its totient is φ = 231830242560.

The previous prime is 721201809793. The next prime is 721201809871. The reversal of 721201809816 is 618908102127.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 82959166 + ... + 82967858.

It is an arithmetic number, because the mean of its divisors is an integer number (10542692160).

Almost surely, 2^721201809816 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 721201809816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1012098447360).

721201809816 is an abundant number, since it is smaller than the sum of its proper divisors (1302995084904).

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

721201809816 is a wasteful number, since it uses less digits than its factorization.

721201809816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9086 (or 9079 counting only the distinct ones).

The product of its (nonzero) digits is 96768, while the sum is 45.

The spelling of 721201809816 in words is "seven hundred twenty-one billion, two hundred one million, eight hundred nine thousand, eight hundred sixteen".