721888 has 24 divisors (see below), whose sum is σ = 1505952. Its totient is φ = 339456.

The previous prime is 721883. The next prime is 721891. The reversal of 721888 is 888127.

It is a super-2 number, since 2×721888² = 1042244569088, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (34).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721883) by changing a digit.

721888 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 120 + ... + 1207.

It is an arithmetic number, because the mean of its divisors is an integer number (62748).

2⁷²¹⁸⁸⁸ is an apocalyptic number.

It is an amenable number.

721888 is an abundant number, since it is smaller than the sum of its proper divisors (784064).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

721888 is a wasteful number, since it uses less digits than its factorization.

721888 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1354 (or 1346 counting only the distinct ones).

The product of its digits is 7168, while the sum is 34.

The square root of 721888 is about 849.6399237324. The cubic root of 721888 is about 89.7063681485.

The spelling of 721888 in words is "seven hundred twenty-one thousand, eight hundred eighty-eight".