161820604 has 48 divisors (see below), whose sum is σ = 318592512. Its totient is φ = 71280000.

The previous prime is 161820599. The next prime is 161820613. The reversal of 161820604 is 406028161.

It is a Smith number, since the sum of its digits (28) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 488719 + ... + 489049.

It is an arithmetic number, because the mean of its divisors is an integer number (6637344).

Almost surely, 2^161820604 is an apocalyptic number.

It is an amenable number.

161820604 is a deficient number, since it is larger than the sum of its proper divisors (156771908).

161820604 is a wasteful number, since it uses less digits than its factorization.

161820604 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 658 (or 656 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 28.

The square root of 161820604 is about 12720.8727688001. The cubic root of 161820604 is about 544.9348787325.

Adding to 161820604 its reverse (406028161), we get a palindrome (567848765).

It can be divided in two parts, 1618 and 20604, that added together give a palindrome (22222).

The spelling of 161820604 in words is "one hundred sixty-one million, eight hundred twenty thousand, six hundred four".