72868561 has 4 divisors (see below), whose sum is σ = 75381300. Its totient is φ = 70355824.

The previous prime is 72868559. The next prime is 72868583. The reversal of 72868561 is 16586827.

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 62110161 + 10758400 = 7881^2 + 3280^2 .

It is a cyclic number.

It is not a de Polignac number, because 72868561 - 2¹ = 72868559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72868541) 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, 1256326 + ... + 1256383.

It is an arithmetic number, because the mean of its divisors is an integer number (18845325).

Almost surely, 2^72868561 is an apocalyptic number.

It is an amenable number.

72868561 is a deficient number, since it is larger than the sum of its proper divisors (2512739).

72868561 is a wasteful number, since it uses less digits than its factorization.

72868561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2512738.

The product of its digits is 161280, while the sum is 43.

The square root of 72868561 is about 8536.3083941479. The cubic root of 72868561 is about 417.6829341634.

The spelling of 72868561 in words is "seventy-two million, eight hundred sixty-eight thousand, five hundred sixty-one".