72911569121 has 4 divisors (see below), whose sum is σ = 72918769044. Its totient is φ = 72904369200.

The previous prime is 72911569063. The next prime is 72911569147. The reversal of 72911569121 is 12196511927.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12196511927 = 5171 ⋅2358637.

It can be written as a sum of positive squares in 2 ways, for example, as 41275610896 + 31635958225 = 203164^2 + 177865^2 .

It is a cyclic number.

It is not a de Polignac number, because 72911569121 - 2¹⁰ = 72911568097 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (72911569021) 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, 3584750 + ... + 3605031.

It is an arithmetic number, because the mean of its divisors is an integer number (18229692261).

Almost surely, 2^72911569121 is an apocalyptic number.

It is an amenable number.

72911569121 is a deficient number, since it is larger than the sum of its proper divisors (7199923).

72911569121 is a wasteful number, since it uses less digits than its factorization.

72911569121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7199922.

The product of its digits is 68040, while the sum is 44.

The spelling of 72911569121 in words is "seventy-two billion, nine hundred eleven million, five hundred sixty-nine thousand, one hundred twenty-one".