721420 has 24 divisors (see below), whose sum is σ = 1731744. Its totient is φ = 247296.

The previous prime is 721397. The next prime is 721439. The reversal of 721420 is 24127.

It is a junction number, because it is equal to n+sod(n) for n = 721394 and 721403.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2437 + ... + 2716.

It is an arithmetic number, because the mean of its divisors is an integer number (72156).

2⁷²¹⁴²⁰ is an apocalyptic number.

721420 is a gapful number since it is divisible by the number (70) formed by its first and last digit.

It is an amenable number.

721420 is an abundant number, since it is smaller than the sum of its proper divisors (1010324).

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

721420 is a wasteful number, since it uses less digits than its factorization.

721420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5169 (or 5167 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 16.

The square root of 721420 is about 849.3644682938. The cubic root of 721420 is about 89.6869784112.

Adding to 721420 its reverse (24127), we get a palindrome (745547).

The spelling of 721420 in words is "seven hundred twenty-one thousand, four hundred twenty", and thus it is an iban number.