72911569021 has 2 divisors, whose sum is σ = 72911569022. Its totient is φ = 72911569020.

The previous prime is 72911568973. The next prime is 72911569043. The reversal of 72911569021 is 12096511927.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 50825448025 + 22086120996 = 225445^2 + 148614^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-72911569021 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (72911569051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36455784510 + 36455784511.

It is an arithmetic number, because the mean of its divisors is an integer number (36455784511).

Almost surely, 2^72911569021 is an apocalyptic number.

It is an amenable number.

72911569021 is a deficient number, since it is larger than the sum of its proper divisors (1).

72911569021 is an equidigital number, since it uses as much as digits as its factorization.

72911569021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 68040, while the sum is 43.

The spelling of 72911569021 in words is "seventy-two billion, nine hundred eleven million, five hundred sixty-nine thousand, twenty-one".