66372541561 has 4 divisors (see below), whose sum is σ = 66850042000. Its totient is φ = 65895041124.

The previous prime is 66372541549. The next prime is 66372541603. The reversal of 66372541561 is 16514527366.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 66372541561 - 2²⁵ = 66338987129 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66372541531) 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, 238750011 + ... + 238750288.

It is an arithmetic number, because the mean of its divisors is an integer number (16712510500).

Almost surely, 2^66372541561 is an apocalyptic number.

It is an amenable number.

66372541561 is a deficient number, since it is larger than the sum of its proper divisors (477500439).

66372541561 is a wasteful number, since it uses less digits than its factorization.

66372541561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 477500438.

The product of its digits is 907200, while the sum is 46.

The spelling of 66372541561 in words is "sixty-six billion, three hundred seventy-two million, five hundred forty-one thousand, five hundred sixty-one".