66138913091 has 8 divisors (see below), whose sum is σ = 69276936960. Its totient is φ = 63022757512.

The previous prime is 66138913073. The next prime is 66138913103. The reversal of 66138913091 is 19031983166.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 66138913091 - 2¹⁰ = 66138912067 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66138913021) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5460881 + ... + 5472978.

It is an arithmetic number, because the mean of its divisors is an integer number (8659617120).

Almost surely, 2^66138913091 is an apocalyptic number.

66138913091 is a deficient number, since it is larger than the sum of its proper divisors (3138023869).

66138913091 is a wasteful number, since it uses less digits than its factorization.

66138913091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10934145.

The product of its (nonzero) digits is 209952, while the sum is 47.

The spelling of 66138913091 in words is "sixty-six billion, one hundred thirty-eight million, nine hundred thirteen thousand, ninety-one".