165706607561 has 4 divisors (see below), whose sum is σ = 180770844624. Its totient is φ = 150642370500.

The previous prime is 165706607527. The next prime is 165706607593.

165706607561 is nontrivially palindromic in base 10.

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 165706607561 - 2²² = 165702413257 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165706601561) 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, 7532118515 + ... + 7532118536.

It is an arithmetic number, because the mean of its divisors is an integer number (45192711156).

Almost surely, 2^165706607561 is an apocalyptic number.

165706607561 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

165706607561 is a deficient number, since it is larger than the sum of its proper divisors (15064237063).

165706607561 is a wasteful number, since it uses less digits than its factorization.

165706607561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15064237062.

The product of its (nonzero) digits is 1587600, while the sum is 50.

The spelling of 165706607561 in words is "one hundred sixty-five billion, seven hundred six million, six hundred seven thousand, five hundred sixty-one".