721640073 has 16 divisors (see below), whose sum is σ = 1199609856. Its totient is φ = 374877840.

The previous prime is 721640071. The next prime is 721640081. The reversal of 721640073 is 370046127.

It is not a de Polignac number, because 721640073 - 2¹ = 721640071 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 721640073.

It is not an unprimeable number, because it can be changed into a prime (721640071) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1561761 + ... + 1562222.

It is an arithmetic number, because the mean of its divisors is an integer number (74975616).

Almost surely, 2^721640073 is an apocalyptic number.

It is an amenable number.

721640073 is a deficient number, since it is larger than the sum of its proper divisors (477969783).

721640073 is a wasteful number, since it uses less digits than its factorization.

721640073 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3124004.

The product of its (nonzero) digits is 7056, while the sum is 30.

The square root of 721640073 is about 26863.3593022168. The cubic root of 721640073 is about 896.9609731358.

The spelling of 721640073 in words is "seven hundred twenty-one million, six hundred forty thousand, seventy-three".