721671601 has 4 divisors (see below), whose sum is σ = 824767552. Its totient is φ = 618575652.

The previous prime is 721671593. The next prime is 721671617. The reversal of 721671601 is 106176127.

721671601 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 106176127 = 7883 ⋅13469.

It is a cyclic number.

It is not a de Polignac number, because 721671601 - 2³ = 721671593 is a prime.

It is not an unprimeable number, because it can be changed into a prime (721671631) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 51547965 + ... + 51547978.

It is an arithmetic number, because the mean of its divisors is an integer number (206191888).

Almost surely, 2^721671601 is an apocalyptic number.

It is an amenable number.

721671601 is a deficient number, since it is larger than the sum of its proper divisors (103095951).

721671601 is a wasteful number, since it uses less digits than its factorization.

721671601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 103095950.

The product of its (nonzero) digits is 3528, while the sum is 31.

The square root of 721671601 is about 26863.9461174266. The cubic root of 721671601 is about 896.9740354988.

The spelling of 721671601 in words is "seven hundred twenty-one million, six hundred seventy-one thousand, six hundred one".