72320400 has 90 divisors (see below), whose sum is σ = 250984370. Its totient is φ = 19284480.

The previous prime is 72320399. The next prime is 72320407. The reversal of 72320400 is 402327.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 138384 + 72182016 = 372^2 + 8496^2 .

It is a tau number, because it is divible by the number of its divisors (90).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (72320407) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 6445 + ... + 13644.

Almost surely, 2^72320400 is an apocalyptic number.

It is an amenable number.

72320400 is an abundant number, since it is smaller than the sum of its proper divisors (178663970).

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

72320400 is a wasteful number, since it uses less digits than its factorization.

72320400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20113 (or 20099 counting only the distinct ones).

The product of its (nonzero) digits is 336, while the sum is 18.

The square root of 72320400 is about 8504.1401681769. The cubic root of 72320400 is about 416.6329430484.

Adding to 72320400 its reverse (402327), we get a palindrome (72722727).

The spelling of 72320400 in words is "seventy-two million, three hundred twenty thousand, four hundred".