724665840 has 80 divisors (see below), whose sum is σ = 2250787488. Its totient is φ = 192872448.

The previous prime is 724665829. The next prime is 724665841. The reversal of 724665840 is 48566427.

It is a tau number, because it is divible by the number of its divisors (80).

It is a hoax number, since the sum of its digits (42) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 724665792 and 724665801.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (724665841) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 135864 + ... + 141096.

Almost surely, 2^724665840 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 724665840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1125393744).

724665840 is an abundant number, since it is smaller than the sum of its proper divisors (1526121648).

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

724665840 is a wasteful number, since it uses less digits than its factorization.

724665840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5826 (or 5820 counting only the distinct ones).

The product of its (nonzero) digits is 322560, while the sum is 42.

The square root of 724665840 is about 26919.6181250775. The cubic root of 724665840 is about 898.2128486218.

The spelling of 724665840 in words is "seven hundred twenty-four million, six hundred sixty-five thousand, eight hundred forty".