66561053242 has 4 divisors (see below), whose sum is σ = 99841579866. Its totient is φ = 33280526620.

The previous prime is 66561053231. The next prime is 66561053249. The reversal of 66561053242 is 24235016566.

It is a happy number.

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

It can be written as a sum of positive squares in only one way, i.e., 37776198321 + 28784854921 = 194361^2 + 169661^2 .

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a junction number, because it is equal to n+sod(n) for n = 66561053195 and 66561053204.

It is not an unprimeable number, because it can be changed into a prime (66561053249) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 16640263309 + ... + 16640263312.

Almost surely, 2^66561053242 is an apocalyptic number.

66561053242 is a deficient number, since it is larger than the sum of its proper divisors (33280526624).

66561053242 is a wasteful number, since it uses less digits than its factorization.

66561053242 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33280526623.

The product of its (nonzero) digits is 259200, while the sum is 40.

The spelling of 66561053242 in words is "sixty-six billion, five hundred sixty-one million, fifty-three thousand, two hundred forty-two".