66512221566 has 32 divisors (see below), whose sum is σ = 152379080448. Its totient is φ = 18959598720.

The previous prime is 66512221493. The next prime is 66512221571.

It is a happy number.

66512221566 is nontrivially palindromic in base 10.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1810480 + ... + 1846851.

It is an arithmetic number, because the mean of its divisors is an integer number (4761846264).

Almost surely, 2^66512221566 is an apocalyptic number.

66512221566 is an abundant number, since it is smaller than the sum of its proper divisors (85866858882).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66512221566 is a wasteful number, since it uses less digits than its factorization.

66512221566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3657776.

The product of its digits is 259200, while the sum is 42.

The spelling of 66512221566 in words is "sixty-six billion, five hundred twelve million, two hundred twenty-one thousand, five hundred sixty-six".