66688220851 has 12 divisors (see below), whose sum is σ = 79380191352. Its totient is φ = 55831997088.

The previous prime is 66688220843. The next prime is 66688220869. The reversal of 66688220851 is 15802288666.

It is not a de Polignac number, because 66688220851 - 2³ = 66688220843 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66688220881) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 15823290 + ... + 15827503.

It is an arithmetic number, because the mean of its divisors is an integer number (6615015946).

Almost surely, 2^66688220851 is an apocalyptic number.

66688220851 is a deficient number, since it is larger than the sum of its proper divisors (12691970501).

66688220851 is a wasteful number, since it uses less digits than its factorization.

66688220851 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31650850 (or 31650843 counting only the distinct ones).

The product of its (nonzero) digits is 2211840, while the sum is 52.

The spelling of 66688220851 in words is "sixty-six billion, six hundred eighty-eight million, two hundred twenty thousand, eight hundred fifty-one".