66229916921 has 16 divisors (see below), whose sum is σ = 75993759744. Its totient is φ = 56541841344.

The previous prime is 66229916911. The next prime is 66229916971. The reversal of 66229916921 is 12961992266.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 66229916921 - 2²² = 66225722617 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (66229916911) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6942671 + ... + 6952203.

It is an arithmetic number, because the mean of its divisors is an integer number (4749609984).

Almost surely, 2^66229916921 is an apocalyptic number.

It is an amenable number.

66229916921 is a deficient number, since it is larger than the sum of its proper divisors (9763842823).

66229916921 is a wasteful number, since it uses less digits than its factorization.

66229916921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13400.

The product of its digits is 1259712, while the sum is 53.

The spelling of 66229916921 in words is "sixty-six billion, two hundred twenty-nine million, nine hundred sixteen thousand, nine hundred twenty-one".