72701565661 has 2 divisors, whose sum is σ = 72701565662. Its totient is φ = 72701565660.

The previous prime is 72701565647. The next prime is 72701565683. The reversal of 72701565661 is 16656510727.

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., 50324397561 + 22377168100 = 224331^2 + 149590^2 .

It is an emirp because it is prime and its reverse (16656510727) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 72701565661 - 2¹³ = 72701557469 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (72701565361) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36350782830 + 36350782831.

It is an arithmetic number, because the mean of its divisors is an integer number (36350782831).

Almost surely, 2^72701565661 is an apocalyptic number.

It is an amenable number.

72701565661 is a deficient number, since it is larger than the sum of its proper divisors (1).

72701565661 is an equidigital number, since it uses as much as digits as its factorization.

72701565661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 529200, while the sum is 46.

The spelling of 72701565661 in words is "seventy-two billion, seven hundred one million, five hundred sixty-five thousand, six hundred sixty-one".