66985973542 has 4 divisors (see below), whose sum is σ = 100478960316. Its totient is φ = 33492986770.

The previous prime is 66985973533. The next prime is 66985973543. The reversal of 66985973542 is 24537958966.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66985973543) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 16746493384 + ... + 16746493387.

It is an arithmetic number, because the mean of its divisors is an integer number (25119740079).

Almost surely, 2^66985973542 is an apocalyptic number.

66985973542 is a deficient number, since it is larger than the sum of its proper divisors (33492986774).

66985973542 is a wasteful number, since it uses less digits than its factorization.

66985973542 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33492986773.

The product of its digits is 97977600, while the sum is 64.

The spelling of 66985973542 in words is "sixty-six billion, nine hundred eighty-five million, nine hundred seventy-three thousand, five hundred forty-two".