1601604 has 36 divisors (see below), whose sum is σ = 4288284. Its totient is φ = 502272.

The previous prime is 1601599. The next prime is 1601609. The reversal of 1601604 is 4061061.

1601604 is a `hidden beast` number, since 1 + 60 + 1 + 604 = 666.

It is an interprime number because it is at equal distance from previous prime (1601599) and next prime (1601609).

It can be written as a sum of positive squares in 2 ways, for example, as 1440000 + 161604 = 1200^2 + 402^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1601609) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 697 + ... + 1920.

It is an arithmetic number, because the mean of its divisors is an integer number (119119).

2^1601604 is an apocalyptic number.

It is an amenable number.

1601604 is an abundant number, since it is smaller than the sum of its proper divisors (2686680).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1601604 is a wasteful number, since it uses less digits than its factorization.

1601604 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2644 (or 2639 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

The square root of 1601604 is about 1265.5449419124. The cubic root of 1601604 is about 116.9997808455. Note that the first 3 decimals are identical.

Adding to 1601604 its reverse (4061061), we get a palindrome (5662665).

It can be divided in two parts, 160 and 1604, that added together give a square (1764 = 42²).

The spelling of 1601604 in words is "one million, six hundred one thousand, six hundred four".