165661151261 has 4 divisors (see below), whose sum is σ = 165663112224. Its totient is φ = 165659190300.

The previous prime is 165661151213. The next prime is 165661151311. The reversal of 165661151261 is 162151166561.

It is a happy number.

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 a cyclic number.

It is not a de Polignac number, because 165661151261 - 2³⁴ = 148481282077 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165661156261) 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, 847775 + ... + 1024716.

It is an arithmetic number, because the mean of its divisors is an integer number (41415778056).

Almost surely, 2^165661151261 is an apocalyptic number.

It is an amenable number.

165661151261 is a deficient number, since it is larger than the sum of its proper divisors (1960963).

165661151261 is an equidigital number, since it uses as much as digits as its factorization.

165661151261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1960962.

The product of its digits is 64800, while the sum is 41.

The spelling of 165661151261 in words is "one hundred sixty-five billion, six hundred sixty-one million, one hundred fifty-one thousand, two hundred sixty-one".