721897 has 16 divisors (see below), whose sum is σ = 852480. Its totient is φ = 604800.

The previous prime is 721891. The next prime is 721909. The reversal of 721897 is 798127.

721897 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 721897 - 2¹⁹ = 197609 is a prime.

It is a super-2 number, since 2×721897² = 1042270557218, which contains 22 as substring.

It is a Duffinian number.

Its product of digits (7056) is a multiple of the sum of its prime divisors (144).

It is not an unprimeable number, because it can be changed into a prime (721891) 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, 9853 + ... + 9925.

It is an arithmetic number, because the mean of its divisors is an integer number (53280).

2⁷²¹⁸⁹⁷ is an apocalyptic number.

It is an amenable number.

721897 is a deficient number, since it is larger than the sum of its proper divisors (130583).

721897 is a wasteful number, since it uses less digits than its factorization.

721897 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 144.

The product of its digits is 7056, while the sum is 34.

The square root of 721897 is about 849.6452200772. The cubic root of 721897 is about 89.7067409459.

It can be divided in two parts, 7 and 21897, that added together give a square (21904 = 148²).

The spelling of 721897 in words is "seven hundred twenty-one thousand, eight hundred ninety-seven".