721855 has 8 divisors (see below), whose sum is σ = 904032. Its totient is φ = 552288.

The previous prime is 721849. The next prime is 721859. The reversal of 721855 is 558127.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 721855 - 2¹³ = 713663 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721859) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3024 + ... + 3253.

It is an arithmetic number, because the mean of its divisors is an integer number (113004).

2⁷²¹⁸⁵⁵ is an apocalyptic number.

721855 is a deficient number, since it is larger than the sum of its proper divisors (182177).

721855 is a wasteful number, since it uses less digits than its factorization.

721855 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6305.

The product of its digits is 2800, while the sum is 28.

The square root of 721855 is about 849.6205035191. The cubic root of 721855 is about 89.7050011981.

The spelling of 721855 in words is "seven hundred twenty-one thousand, eight hundred fifty-five".