166561563 has 32 divisors (see below), whose sum is σ = 273839616. Its totient is φ = 87879168.

The previous prime is 166561553. The next prime is 166561573. The reversal of 166561563 is 365165661.

It is an interprime number because it is at equal distance from previous prime (166561553) and next prime (166561573).

It is not a de Polignac number, because 166561563 - 2¹³ = 166553371 is a prime.

It is not an unprimeable number, because it can be changed into a prime (166561523) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 14520 + ... + 23322.

It is an arithmetic number, because the mean of its divisors is an integer number (8557488).

Almost surely, 2^166561563 is an apocalyptic number.

166561563 is a deficient number, since it is larger than the sum of its proper divisors (107278053).

166561563 is a wasteful number, since it uses less digits than its factorization.

166561563 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8883.

The product of its digits is 97200, while the sum is 39.

The square root of 166561563 is about 12905.8731978894. The cubic root of 166561563 is about 550.2055022698.

The spelling of 166561563 in words is "one hundred sixty-six million, five hundred sixty-one thousand, five hundred sixty-three".