166561166001 has 4 divisors (see below), whose sum is σ = 222081554672. Its totient is φ = 111040777332.

The previous prime is 166561165993. The next prime is 166561166029. The reversal of 166561166001 is 100661165661.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 166561166001 - 2³ = 166561165993 is a prime.

It is a super-2 number, since 2×166561166001² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (166561166081) 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, 27760194331 + ... + 27760194336.

It is an arithmetic number, because the mean of its divisors is an integer number (55520388668).

Almost surely, 2^166561166001 is an apocalyptic number.

It is an amenable number.

166561166001 is a deficient number, since it is larger than the sum of its proper divisors (55520388671).

166561166001 is an equidigital number, since it uses as much as digits as its factorization.

166561166001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55520388670.

The product of its (nonzero) digits is 38880, while the sum is 39.

The spelling of 166561166001 in words is "one hundred sixty-six billion, five hundred sixty-one million, one hundred sixty-six thousand, one".