7720400 has 30 divisors (see below), whose sum is σ = 18549222. Its totient is φ = 3088000.

The previous prime is 7720399. The next prime is 7720429. The reversal of 7720400 is 40277.

It can be written as a sum of positive squares in 3 ways, for example, as 602176 + 7118224 = 776^2 + 2668^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 9251 + ... + 10050.

Almost surely, 2^7720400 is an apocalyptic number.

It is an amenable number.

7720400 is an abundant number, since it is smaller than the sum of its proper divisors (10828822).

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

7720400 is a wasteful number, since it uses less digits than its factorization.

7720400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19319 (or 19308 counting only the distinct ones).

The product of its (nonzero) digits is 392, while the sum is 20.

The square root of 7720400 is about 2778.5607785327. The cubic root of 7720400 is about 197.6423158403.

Adding to 7720400 its reverse (40277), we get a palindrome (7760677).

The spelling of 7720400 in words is "seven million, seven hundred twenty thousand, four hundred".