72399440 has 40 divisors (see below), whose sum is σ = 172442088. Its totient is φ = 28252160.

The previous prime is 72399433. The next prime is 72399449. The reversal of 72399440 is 4499327.

It can be written as a sum of positive squares in 4 ways, for example, as 8271376 + 64128064 = 2876^2 + 8008^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a junction number, because it is equal to n+sod(n) for n = 72399394 and 72399403.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72399449) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7757 + ... + 14316.

Almost surely, 2^72399440 is an apocalyptic number.

It is an amenable number.

72399440 is an abundant number, since it is smaller than the sum of its proper divisors (100042648).

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

72399440 is a wasteful number, since it uses less digits than its factorization.

72399440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22127 (or 22121 counting only the distinct ones).

The product of its (nonzero) digits is 54432, while the sum is 38.

The square root of 72399440 is about 8508.7860473748. The cubic root of 72399440 is about 416.7846691556.

The spelling of 72399440 in words is "seventy-two million, three hundred ninety-nine thousand, four hundred forty".