66821157772 has 6 divisors (see below), whose sum is σ = 116937026108. Its totient is φ = 33410578884.

The previous prime is 66821157719. The next prime is 66821157773. The reversal of 66821157772 is 27775112866.

It is not an unprimeable number, because it can be changed into a prime (66821157773) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8352644718 + ... + 8352644725.

Almost surely, 2^66821157772 is an apocalyptic number.

It is an amenable number.

66821157772 is a deficient number, since it is larger than the sum of its proper divisors (50115868336).

66821157772 is a wasteful number, since it uses less digits than its factorization.

66821157772 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16705289447 (or 16705289445 counting only the distinct ones).

The product of its digits is 1975680, while the sum is 52.

The spelling of 66821157772 in words is "sixty-six billion, eight hundred twenty-one million, one hundred fifty-seven thousand, seven hundred seventy-two".