21120404 has 6 divisors (see below), whose sum is σ = 36960714. Its totient is φ = 10560200.

The previous prime is 21120403. The next prime is 21120427. The reversal of 21120404 is 40402112.

It can be written as a sum of positive squares in only one way, i.e., 19802500 + 1317904 = 4450^2 + 1148^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21120403) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2640047 + ... + 2640054.

It is an arithmetic number, because the mean of its divisors is an integer number (6160119).

Almost surely, 2^21120404 is an apocalyptic number.

It is an amenable number.

21120404 is a deficient number, since it is larger than the sum of its proper divisors (15840310).

21120404 is a wasteful number, since it uses less digits than its factorization.

21120404 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5280105 (or 5280103 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 14.

The square root of 21120404 is about 4595.6940716284. The cubic root of 21120404 is about 276.4186916961.

Adding to 21120404 its reverse (40402112), we get a palindrome (61522516).

The spelling of 21120404 in words is "twenty-one million, one hundred twenty thousand, four hundred four".