66905880847 has 4 divisors (see below), whose sum is σ = 72052487080. Its totient is φ = 61759274616.

The previous prime is 66905880823. The next prime is 66905880863. The reversal of 66905880847 is 74808850966.

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

It is a de Polignac number, because none of the positive numbers 2^k-66905880847 is a prime.

It is a super-2 number, since 2×66905880847² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66905880047) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2573303097 + ... + 2573303122.

It is an arithmetic number, because the mean of its divisors is an integer number (18013121770).

Almost surely, 2^66905880847 is an apocalyptic number.

66905880847 is a deficient number, since it is larger than the sum of its proper divisors (5146606233).

66905880847 is a wasteful number, since it uses less digits than its factorization.

66905880847 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5146606232.

The product of its (nonzero) digits is 23224320, while the sum is 61.

The spelling of 66905880847 in words is "sixty-six billion, nine hundred five million, eight hundred eighty thousand, eight hundred forty-seven".