721155 has 16 divisors (see below), whose sum is σ = 1165824. Its totient is φ = 380640.

The previous prime is 721141. The next prime is 721159. The reversal of 721155 is 551127.

It is not a de Polignac number, because 721155 - 2⁴ = 721139 is a prime.

It is not an unprimeable number, because it can be changed into a prime (721159) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1782 + ... + 2148.

It is an arithmetic number, because the mean of its divisors is an integer number (72864).

2⁷²¹¹⁵⁵ is an apocalyptic number.

721155 is a deficient number, since it is larger than the sum of its proper divisors (444669).

721155 is a wasteful number, since it uses less digits than its factorization.

721155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 506.

The product of its digits is 350, while the sum is 21.

The square root of 721155 is about 849.2084549744. The cubic root of 721155 is about 89.6759954609.

The spelling of 721155 in words is "seven hundred twenty-one thousand, one hundred fifty-five".