721400 has 24 divisors (see below), whose sum is σ = 1677720. Its totient is φ = 288480.

The previous prime is 721397. The next prime is 721439. The reversal of 721400 is 4127.

721400 = T₁₃ + T₁₄ + ... + T₁₆₂.

It is a happy number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 721400.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1604 + ... + 2003.

It is an arithmetic number, because the mean of its divisors is an integer number (69905).

2⁷²¹⁴⁰⁰ is an apocalyptic number.

It is an amenable number.

721400 is an abundant number, since it is smaller than the sum of its proper divisors (956320).

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

721400 is a wasteful number, since it uses less digits than its factorization.

721400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3623 (or 3614 counting only the distinct ones).

The product of its (nonzero) digits is 56, while the sum is 14.

The square root of 721400 is about 849.3526947034. The cubic root of 721400 is about 89.6861496031.

Adding to 721400 its reverse (4127), we get a palindrome (725527).

The spelling of 721400 in words is "seven hundred twenty-one thousand, four hundred", and thus it is an iban number.