721591398064 has 40 divisors (see below), whose sum is σ = 1409504071680. Its totient is φ = 357850075968.

The previous prime is 721591398023. The next prime is 721591398079. The reversal of 721591398064 is 460893195127.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 721591397996 and 721591398014.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7141077 + ... + 7241419.

It is an arithmetic number, because the mean of its divisors is an integer number (35237601792).

It is a 1-persistent number, because it is pandigital, but 2⋅721591398064 = 1443182796128 is not.

Almost surely, 2^721591398064 is an apocalyptic number.

It is an amenable number.

721591398064 is a deficient number, since it is larger than the sum of its proper divisors (687912673616).

721591398064 is a wasteful number, since it uses less digits than its factorization.

721591398064 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 104017 (or 104011 counting only the distinct ones).

The product of its (nonzero) digits is 3265920, while the sum is 55.

The spelling of 721591398064 in words is "seven hundred twenty-one billion, five hundred ninety-one million, three hundred ninety-eight thousand, sixty-four".