66889637881 has 4 divisors (see below), whose sum is σ = 72970514064. Its totient is φ = 60808761700.

The previous prime is 66889637861. The next prime is 66889637891. The reversal of 66889637881 is 18873698866.

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 66889637881 - 2²⁹ = 66352766969 is a prime.

It is a super-2 number, since 2×66889637881² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 66889637881.

It is not an unprimeable number, because it can be changed into a prime (66889637851) 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, 3040438075 + ... + 3040438096.

It is an arithmetic number, because the mean of its divisors is an integer number (18242628516).

Almost surely, 2^66889637881 is an apocalyptic number.

It is an amenable number.

66889637881 is a deficient number, since it is larger than the sum of its proper divisors (6080876183).

66889637881 is a wasteful number, since it uses less digits than its factorization.

66889637881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6080876182.

The product of its digits is 167215104, while the sum is 70.

The spelling of 66889637881 in words is "sixty-six billion, eight hundred eighty-nine million, six hundred thirty-seven thousand, eight hundred eighty-one".