165521774001 has 4 divisors (see below), whose sum is σ = 220695698672. Its totient is φ = 110347849332.

The previous prime is 165521773993. The next prime is 165521774017. The reversal of 165521774001 is 100477125561.

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 165521774001 - 2³ = 165521773993 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165521774021) 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, 27586962331 + ... + 27586962336.

It is an arithmetic number, because the mean of its divisors is an integer number (55173924668).

Almost surely, 2^165521774001 is an apocalyptic number.

It is an amenable number.

165521774001 is a deficient number, since it is larger than the sum of its proper divisors (55173924671).

165521774001 is an equidigital number, since it uses as much as digits as its factorization.

165521774001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55173924670.

The product of its (nonzero) digits is 58800, while the sum is 39.

Adding to 165521774001 its reverse (100477125561), we get a palindrome (265998899562).

The spelling of 165521774001 in words is "one hundred sixty-five billion, five hundred twenty-one million, seven hundred seventy-four thousand, one".