163551661 has 32 divisors (see below), whose sum is σ = 210425600. Its totient is φ = 126245952.

The previous prime is 163551659. The next prime is 163551671. The reversal of 163551661 is 166155361.

It is not a de Polignac number, because 163551661 - 2¹ = 163551659 is a prime.

It is a hoax number, since the sum of its digits (34) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (163551671) 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, 191311 + ... + 192163.

It is an arithmetic number, because the mean of its divisors is an integer number (6575800).

Almost surely, 2^163551661 is an apocalyptic number.

It is an amenable number.

163551661 is a deficient number, since it is larger than the sum of its proper divisors (46873939).

163551661 is an equidigital number, since it uses as much as digits as its factorization.

163551661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 930 (or 916 counting only the distinct ones).

The product of its digits is 16200, while the sum is 34.

The square root of 163551661 is about 12788.7317979540. The cubic root of 163551661 is about 546.8711165591.

The spelling of 163551661 in words is "one hundred sixty-three million, five hundred fifty-one thousand, six hundred sixty-one".