721947438240 has 768 divisors, whose sum is σ = 2729619357696. Its totient is φ = 156938342400.

The previous prime is 721947438227. The next prime is 721947438253. The reversal of 721947438240 is 42834749127.

It is an interprime number because it is at equal distance from previous prime (721947438227) and next prime (721947438253).

It is a super-2 number, since 2×721947438240² (a number of 25 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (51) coincides with the sum of the digits of its prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 2351620167 + ... + 2351620473.

It is an arithmetic number, because the mean of its divisors is an integer number (3554191872).

Almost surely, 2^721947438240 is an apocalyptic number.

721947438240 is a gapful number since it is divisible by the number (70) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 721947438240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1364809678848).

721947438240 is an abundant number, since it is smaller than the sum of its proper divisors (2007671919456).

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

721947438240 is a wasteful number, since it uses less digits than its factorization.

721947438240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 681 (or 673 counting only the distinct ones).

The product of its (nonzero) digits is 2709504, while the sum is 51.

The spelling of 721947438240 in words is "seven hundred twenty-one billion, nine hundred forty-seven million, four hundred thirty-eight thousand, two hundred forty".