66121378839 has 20 divisors (see below), whose sum is σ = 99034574760. Its totient is φ = 43964590320.

The previous prime is 66121378831. The next prime is 66121378861. The reversal of 66121378839 is 93887312166.

66121378839 is a `hidden beast` number, since 6 + 612 + 13 + 7 + 8 + 8 + 3 + 9 = 666.

It is not a de Polignac number, because 66121378839 - 2³ = 66121378831 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66121378831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 1046232 + ... + 1107629.

It is an arithmetic number, because the mean of its divisors is an integer number (4951728738).

Almost surely, 2^66121378839 is an apocalyptic number.

66121378839 is a deficient number, since it is larger than the sum of its proper divisors (32913195921).

66121378839 is a wasteful number, since it uses less digits than its factorization.

66121378839 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2154252 (or 2154243 counting only the distinct ones).

The product of its digits is 2612736, while the sum is 54.

The spelling of 66121378839 in words is "sixty-six billion, one hundred twenty-one million, three hundred seventy-eight thousand, eight hundred thirty-nine".