721892 has 6 divisors (see below), whose sum is σ = 1263318. Its totient is φ = 360944.

The previous prime is 721891. The next prime is 721909. The reversal of 721892 is 298127.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 602176 + 119716 = 776^2 + 346^2 .

It is a super-2 number, since 2×721892² = 1042256119328, which contains 22 as substring.

It is an alternating number because its digits alternate between odd and even.

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 as a sum of consecutive naturals, namely, 90233 + ... + 90240.

It is an arithmetic number, because the mean of its divisors is an integer number (210553).

2⁷²¹⁸⁹² is an apocalyptic number.

It is an amenable number.

721892 is a deficient number, since it is larger than the sum of its proper divisors (541426).

721892 is a wasteful number, since it uses less digits than its factorization.

721892 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 180477 (or 180475 counting only the distinct ones).

The product of its digits is 2016, while the sum is 29.

The square root of 721892 is about 849.6422776675. The cubic root of 721892 is about 89.7065338366.

The spelling of 721892 in words is "seven hundred twenty-one thousand, eight hundred ninety-two".