72784720 has 20 divisors (see below), whose sum is σ = 169224660. Its totient is φ = 29113856.

The previous prime is 72784711. The next prime is 72784753. The reversal of 72784720 is 2748727.

It can be written as a sum of positive squares in 2 ways, for example, as 55711296 + 17073424 = 7464^2 + 4132^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a self number, because there is not a number n which added to its sum of digits gives 72784720.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 454825 + ... + 454984.

It is an arithmetic number, because the mean of its divisors is an integer number (8461233).

Almost surely, 2^72784720 is an apocalyptic number.

It is an amenable number.

72784720 is an abundant number, since it is smaller than the sum of its proper divisors (96439940).

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

72784720 is a wasteful number, since it uses less digits than its factorization.

72784720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 909822 (or 909816 counting only the distinct ones).

The product of its (nonzero) digits is 43904, while the sum is 37.

The square root of 72784720 is about 8531.3961342795. The cubic root of 72784720 is about 417.5226803508.

The spelling of 72784720 in words is "seventy-two million, seven hundred eighty-four thousand, seven hundred twenty".