161538663 has 16 divisors (see below), whose sum is σ = 253040256. Its totient is φ = 90371040.

The previous prime is 161538653. The next prime is 161538677. The reversal of 161538663 is 366835161.

It is not a de Polignac number, because 161538663 - 2⁵ = 161538631 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161538623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 187845 + ... + 188702.

It is an arithmetic number, because the mean of its divisors is an integer number (15815016).

Almost surely, 2^161538663 is an apocalyptic number.

161538663 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

161538663 is a deficient number, since it is larger than the sum of its proper divisors (91501593).

161538663 is a wasteful number, since it uses less digits than its factorization.

161538663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 376574.

The product of its digits is 77760, while the sum is 39.

The square root of 161538663 is about 12709.7861114969. The cubic root of 161538663 is about 544.6182136596.

The spelling of 161538663 in words is "one hundred sixty-one million, five hundred thirty-eight thousand, six hundred sixty-three".