721253649373 has 4 divisors (see below), whose sum is σ = 725847621820. Its totient is φ = 716659676928.

The previous prime is 721253649359. The next prime is 721253649377. The reversal of 721253649373 is 373946352127.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 373946352127 = 23 ⋅16258537049.

It can be written as a sum of positive squares in 2 ways, for example, as 279458135044 + 441795514329 = 528638^2 + 664677^2 .

It is a cyclic number.

It is not a de Polignac number, because 721253649373 - 2²¹ = 721251552221 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 721253649373.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721253649377) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2296985988 + ... + 2296986301.

It is an arithmetic number, because the mean of its divisors is an integer number (181461905455).

Almost surely, 2^721253649373 is an apocalyptic number.

It is an amenable number.

721253649373 is a deficient number, since it is larger than the sum of its proper divisors (4593972447).

721253649373 is a wasteful number, since it uses less digits than its factorization.

721253649373 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4593972446.

The product of its digits is 5715360, while the sum is 52.

The spelling of 721253649373 in words is "seven hundred twenty-one billion, two hundred fifty-three million, six hundred forty-nine thousand, three hundred seventy-three".