75721311261 has 24 divisors (see below), whose sum is σ = 112945678560. Its totient is φ = 48854516256.

The previous prime is 75721311251. The next prime is 75721311317. The reversal of 75721311261 is 16211312757.

75721311261 is a `hidden beast` number, since 7 + 572 + 13 + 1 + 12 + 61 = 666.

It is not a de Polignac number, because 75721311261 - 2²³ = 75712922653 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (75721311221) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 855351 + ... + 939716.

It is an arithmetic number, because the mean of its divisors is an integer number (4706069940).

Almost surely, 2^75721311261 is an apocalyptic number.

It is an amenable number.

75721311261 is a deficient number, since it is larger than the sum of its proper divisors (37224367299).

75721311261 is a wasteful number, since it uses less digits than its factorization.

75721311261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1795225 (or 1795222 counting only the distinct ones).

The product of its digits is 17640, while the sum is 36.

The spelling of 75721311261 in words is "seventy-five billion, seven hundred twenty-one million, three hundred eleven thousand, two hundred sixty-one".