764721 has 14 divisors (see below), whose sum is σ = 1147650. Its totient is φ = 509328.

The previous prime is 764719. The next prime is 764723. The reversal of 764721 is 127467.

764721 is nontrivially palindromic in base 7.

It is an interprime number because it is at equal distance from previous prime (764719) and next prime (764723).

It can be written as a sum of positive squares in only one way, i.e., 746496 + 18225 = 864^2 + 135^2 .

It is not a de Polignac number, because 764721 - 2¹ = 764719 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 764721.

It is not an unprimeable number, because it can be changed into a prime (764723) 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 13 ways as a sum of consecutive naturals, for example, 205 + ... + 1253.

It is an arithmetic number, because the mean of its divisors is an integer number (81975).

2⁷⁶⁴⁷²¹ is an apocalyptic number.

It is an amenable number.

764721 is a deficient number, since it is larger than the sum of its proper divisors (382929).

764721 is an equidigital number, since it uses as much as digits as its factorization.

764721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1067 (or 1052 counting only the distinct ones).

The product of its digits is 2352, while the sum is 27.

The square root of 764721 is about 874.4832759979. The cubic root of 764721 is about 91.4466229935.

It can be divided in two parts, 764 and 721, that added together give a triangular number (1485 = T₅₄).

The spelling of 764721 in words is "seven hundred sixty-four thousand, seven hundred twenty-one".