72745078121 has 2 divisors, whose sum is σ = 72745078122. Its totient is φ = 72745078120.

The previous prime is 72745078117. The next prime is 72745078127. The reversal of 72745078121 is 12187054727.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 72509025625 + 236052496 = 269275^2 + 15364^2 .

It is a cyclic number.

It is not a de Polignac number, because 72745078121 - 2² = 72745078117 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is not a weakly prime, because it can be changed into another prime (72745078127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36372539060 + 36372539061.

It is an arithmetic number, because the mean of its divisors is an integer number (36372539061).

Almost surely, 2^72745078121 is an apocalyptic number.

It is an amenable number.

72745078121 is a deficient number, since it is larger than the sum of its proper divisors (1).

72745078121 is an equidigital number, since it uses as much as digits as its factorization.

72745078121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 219520, while the sum is 44.

The spelling of 72745078121 in words is "seventy-two billion, seven hundred forty-five million, seventy-eight thousand, one hundred twenty-one".