21041604 has 36 divisors (see below), whose sum is σ = 54629484. Its totient is φ = 6823872.

The previous prime is 21041599. The next prime is 21041609. The reversal of 21041604 is 40614012.

21041604 is a `hidden beast` number, since 21 + 0 + 41 + 604 = 666.

It is an interprime number because it is at equal distance from previous prime (21041599) and next prime (21041609).

It can be written as a sum of positive squares in 2 ways, for example, as 17239104 + 3802500 = 4152^2 + 1950^2 .

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 not an unprimeable number, because it can be changed into a prime (21041609) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6567 + ... + 9230.

Almost surely, 2^21041604 is an apocalyptic number.

It is an amenable number.

21041604 is an abundant number, since it is smaller than the sum of its proper divisors (33587880).

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

21041604 is a wasteful number, since it uses less digits than its factorization.

21041604 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15844 (or 15839 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 21041604 is about 4587.1128174485. The cubic root of 21041604 is about 276.0744915504.

Adding to 21041604 its reverse (40614012), we get a palindrome (61655616).

It can be divided in two parts, 210 and 41604, that added together give a palindrome (41814).

The spelling of 21041604 in words is "twenty-one million, forty-one thousand, six hundred four".