75363655721 has 4 divisors (see below), whose sum is σ = 77962402500. Its totient is φ = 72764908944.

The previous prime is 75363655687. The next prime is 75363655727. The reversal of 75363655721 is 12755636357.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12755636357 = 112759 ⋅113123.

It can be written as a sum of positive squares in 2 ways, for example, as 20672688400 + 54690967321 = 143780^2 + 233861^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-75363655721 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 75363655721.

It is not an unprimeable number, because it can be changed into a prime (75363655727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1299373346 + ... + 1299373403.

It is an arithmetic number, because the mean of its divisors is an integer number (19490600625).

Almost surely, 2^75363655721 is an apocalyptic number.

It is an amenable number.

75363655721 is a deficient number, since it is larger than the sum of its proper divisors (2598746779).

75363655721 is a wasteful number, since it uses less digits than its factorization.

75363655721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2598746778.

The product of its digits is 3969000, while the sum is 50.

The spelling of 75363655721 in words is "seventy-five billion, three hundred sixty-three million, six hundred fifty-five thousand, seven hundred twenty-one".