721666341 has 80 divisors (see below), whose sum is σ = 1265679360. Its totient is φ = 405090720.

The previous prime is 721666339. The next prime is 721666381. The reversal of 721666341 is 143666127.

It is a happy number.

It is not a de Polignac number, because 721666341 - 2¹ = 721666339 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 721666296 and 721666305.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721666321) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 795210 + ... + 796116.

It is an arithmetic number, because the mean of its divisors is an integer number (15820992).

Almost surely, 2^721666341 is an apocalyptic number.

It is an amenable number.

721666341 is a deficient number, since it is larger than the sum of its proper divisors (544013019).

721666341 is a wasteful number, since it uses less digits than its factorization.

721666341 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 996 (or 987 counting only the distinct ones).

The product of its digits is 36288, while the sum is 36.

The square root of 721666341 is about 26863.8482165158. The cubic root of 721666341 is about 896.9718562551.

The spelling of 721666341 in words is "seven hundred twenty-one million, six hundred sixty-six thousand, three hundred forty-one".