21810104 has 8 divisors (see below), whose sum is σ = 40893960. Its totient is φ = 10905048.

The previous prime is 21810079. The next prime is 21810109. The reversal of 21810104 is 40101812.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21810109) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1363124 + ... + 1363139.

It is an arithmetic number, because the mean of its divisors is an integer number (5111745).

Almost surely, 2^21810104 is an apocalyptic number.

It is an amenable number.

21810104 is a deficient number, since it is larger than the sum of its proper divisors (19083856).

21810104 is a wasteful number, since it uses less digits than its factorization.

21810104 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2726269 (or 2726265 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 17.

The square root of 21810104 is about 4670.1289061438. The cubic root of 21810104 is about 279.3953960990.

Adding to 21810104 its reverse (40101812), we get a palindrome (61911916).

The spelling of 21810104 in words is "twenty-one million, eight hundred ten thousand, one hundred four".