721843261440 has 416 divisors, whose sum is σ = 2794858318080. Its totient is φ = 155285716992.

The previous prime is 721843261417. The next prime is 721843261453. The reversal of 721843261440 is 44162348127.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 721843261392 and 721843261401.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 7261996 + ... + 7360724.

Almost surely, 2^721843261440 is an apocalyptic number.

721843261440 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 721843261440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1397429159040).

721843261440 is an abundant number, since it is smaller than the sum of its proper divisors (2073015056640).

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

721843261440 is a wasteful number, since it uses less digits than its factorization.

721843261440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98785 (or 98763 counting only the distinct ones).

The product of its (nonzero) digits is 258048, while the sum is 42.

The spelling of 721843261440 in words is "seven hundred twenty-one billion, eight hundred forty-three million, two hundred sixty-one thousand, four hundred forty".