720667 has 4 divisors (see below), whose sum is σ = 722376. Its totient is φ = 718960.

The previous prime is 720661. The next prime is 720677. The reversal of 720667 is 766027.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 766027 = 113 ⋅6779.

It is a cyclic number.

It is not a de Polignac number, because 720667 - 2¹⁹ = 196379 is a prime.

It is a Duffinian number.

720667 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (720661) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 288 + ... + 1234.

It is an arithmetic number, because the mean of its divisors is an integer number (180594).

2⁷²⁰⁶⁶⁷ is an apocalyptic number.

720667 is a deficient number, since it is larger than the sum of its proper divisors (1709).

720667 is an equidigital number, since it uses as much as digits as its factorization.

720667 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1708.

The product of its (nonzero) digits is 3528, while the sum is 28.

The square root of 720667 is about 848.9210799597. The cubic root of 720667 is about 89.6557632128.

The spelling of 720667 in words is "seven hundred twenty thousand, six hundred sixty-seven".