721867 has 4 divisors (see below), whose sum is σ = 759880. Its totient is φ = 683856.

The previous prime is 721859. The next prime is 721883. The reversal of 721867 is 768127.

It is a happy number.

721867 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 721867 - 2³ = 721859 is a prime.

It is a Duffinian number.

721867 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (721267) 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, 18978 + ... + 19015.

It is an arithmetic number, because the mean of its divisors is an integer number (189970).

2⁷²¹⁸⁶⁷ is an apocalyptic number.

721867 is a deficient number, since it is larger than the sum of its proper divisors (38013).

721867 is a wasteful number, since it uses less digits than its factorization.

721867 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38012.

The product of its digits is 4704, while the sum is 31.

The square root of 721867 is about 849.6275654662. The cubic root of 721867 is about 89.7054982758.

The spelling of 721867 in words is "seven hundred twenty-one thousand, eight hundred sixty-seven".