721431 has 12 divisors (see below), whose sum is σ = 1057680. Its totient is φ = 473760.

The previous prime is 721397. The next prime is 721439. The reversal of 721431 is 134127.

It is not a de Polignac number, because 721431 - 2¹⁰ = 720407 is a prime.

It is a super-2 number, since 2×721431² = 1040925375522, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721439) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 75 + ... + 1203.

It is an arithmetic number, because the mean of its divisors is an integer number (88140).

2⁷²¹⁴³¹ is an apocalyptic number.

721431 is a gapful number since it is divisible by the number (71) formed by its first and last digit.

721431 is a deficient number, since it is larger than the sum of its proper divisors (336249).

721431 is a wasteful number, since it uses less digits than its factorization.

721431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1206 (or 1203 counting only the distinct ones).

The product of its digits is 168, while the sum is 18.

The square root of 721431 is about 849.3709436989. The cubic root of 721431 is about 89.6874342491.

Adding to 721431 its reverse (134127), we get a palindrome (855558).

The spelling of 721431 in words is "seven hundred twenty-one thousand, four hundred thirty-one".