72763072521661 has 4 divisors (see below), whose sum is σ = 72763979770300. Its totient is φ = 72762165273024.

The previous prime is 72763072521647. The next prime is 72763072521691. The reversal of 72763072521661 is 16612527036727.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 18133382905561 + 54629689616100 = 4258331^2 + 7391190^2 .

It is a cyclic number.

It is not a de Polignac number, because 72763072521661 - 2⁴⁵ = 37578700432829 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72763072521691) 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, 453504006 + ... + 453664423.

It is an arithmetic number, because the mean of its divisors is an integer number (18190994942575).

Almost surely, 2^{72763072521661} is an apocalyptic number.

It is an amenable number.

72763072521661 is a deficient number, since it is larger than the sum of its proper divisors (907248639).

72763072521661 is an equidigital number, since it uses as much as digits as its factorization.

72763072521661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 907248638.

The product of its (nonzero) digits is 8890560, while the sum is 55.

The spelling of 72763072521661 in words is "seventy-two trillion, seven hundred sixty-three billion, seventy-two million, five hundred twenty-one thousand, six hundred sixty-one".