161566651151651 has 4 divisors (see below), whose sum is σ = 163232286730632. Its totient is φ = 159901015572672.

The previous prime is 161566651151597. The next prime is 161566651151671. The reversal of 161566651151651 is 156151156665161.

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

It is a cyclic number.

It is not a de Polignac number, because 161566651151651 - 2³⁴ = 161549471282467 is a prime.

It is a super-4 number, since 4×161566651151651⁴ (a number of 58 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161566651151671) 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, 832817789345 + ... + 832817789538.

It is an arithmetic number, because the mean of its divisors is an integer number (40808071682658).

Almost surely, 2^{161566651151651} is an apocalyptic number.

161566651151651 is a deficient number, since it is larger than the sum of its proper divisors (1665635578981).

161566651151651 is an equidigital number, since it uses as much as digits as its factorization.

161566651151651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1665635578980.

The product of its digits is 4860000, while the sum is 56.

The spelling of 161566651151651 in words is "one hundred sixty-one trillion, five hundred sixty-six billion, six hundred fifty-one million, one hundred fifty-one thousand, six hundred fifty-one".