166561445135642 has 4 divisors (see below), whose sum is σ = 249842167703466. Its totient is φ = 83280722567820.

The previous prime is 166561445135627. The next prime is 166561445135663. The reversal of 166561445135642 is 246531544165661.

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., 151931730471481 + 14629714664161 = 12326059^2 + 3824881^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41640361283909 + ... + 41640361283912.

Almost surely, 2^{166561445135642} is an apocalyptic number.

166561445135642 is a deficient number, since it is larger than the sum of its proper divisors (83280722567824).

166561445135642 is an equidigital number, since it uses as much as digits as its factorization.

166561445135642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83280722567823.

The product of its digits is 62208000, while the sum is 59.

The spelling of 166561445135642 in words is "one hundred sixty-six trillion, five hundred sixty-one billion, four hundred forty-five million, one hundred thirty-five thousand, six hundred forty-two".