66556627157 has 4 divisors (see below), whose sum is σ = 68355454956. Its totient is φ = 64757799360.

The previous prime is 66556627099. The next prime is 66556627183. The reversal of 66556627157 is 75172665566.

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

It can be written as a sum of positive squares in 2 ways, for example, as 44068925476 + 22487701681 = 209926^2 + 149959^2 .

It is a cyclic number.

It is not a de Polignac number, because 66556627157 - 2¹⁸ = 66556365013 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66556623157) 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, 899413844 + ... + 899413917.

It is an arithmetic number, because the mean of its divisors is an integer number (17088863739).

Almost surely, 2^66556627157 is an apocalyptic number.

It is an amenable number.

66556627157 is a deficient number, since it is larger than the sum of its proper divisors (1798827799).

66556627157 is a wasteful number, since it uses less digits than its factorization.

66556627157 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1798827798.

The product of its digits is 15876000, while the sum is 56.

The spelling of 66556627157 in words is "sixty-six billion, five hundred fifty-six million, six hundred twenty-seven thousand, one hundred fifty-seven".