21120104 has 8 divisors (see below), whose sum is σ = 39600210. Its totient is φ = 10560048.

The previous prime is 21120089. The next prime is 21120109. The reversal of 21120104 is 40102112.

It can be written as a sum of positive squares in only one way, i.e., 17623204 + 3496900 = 4198^2 + 1870^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is not an unprimeable number, because it can be changed into a prime (21120109) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1319999 + ... + 1320014.

Almost surely, 2^21120104 is an apocalyptic number.

It is an amenable number.

21120104 is a deficient number, since it is larger than the sum of its proper divisors (18480106).

21120104 is a wasteful number, since it uses less digits than its factorization.

21120104 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2640019 (or 2640015 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 21120104 is about 4595.6614322641. The cubic root of 21120104 is about 276.4173829144.

Adding to 21120104 its reverse (40102112), we get a palindrome (61222216).

The spelling of 21120104 in words is "twenty-one million, one hundred twenty thousand, one hundred four".