66854290391 has 16 divisors (see below), whose sum is σ = 76824204864. Its totient is φ = 56989384704.

The previous prime is 66854290379. The next prime is 66854290421. The reversal of 66854290391 is 19309245866.

It is not a de Polignac number, because 66854290391 - 2³⁰ = 65780548567 is a prime.

It is a super-2 number, since 2×66854290391² (a number of 22 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (53) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66854290361) 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, 6502631 + ... + 6512903.

It is an arithmetic number, because the mean of its divisors is an integer number (4801512804).

Almost surely, 2^66854290391 is an apocalyptic number.

66854290391 is a deficient number, since it is larger than the sum of its proper divisors (9969914473).

66854290391 is a wasteful number, since it uses less digits than its factorization.

66854290391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15290.

The product of its (nonzero) digits is 2799360, while the sum is 53.

The spelling of 66854290391 in words is "sixty-six billion, eight hundred fifty-four million, two hundred ninety thousand, three hundred ninety-one".