21104831 has 16 divisors (see below), whose sum is σ = 24192000. Its totient is φ = 18235200.

The previous prime is 21104819. The next prime is 21104843. The reversal of 21104831 is 13840112.

It is an interprime number because it is at equal distance from previous prime (21104819) and next prime (21104843).

It is a cyclic number.

It is not a de Polignac number, because 21104831 - 2⁶ = 21104767 is a prime.

It is a super-2 number, since 2×21104831² = 890827783077122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21104851) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19595 + ... + 20643.

It is an arithmetic number, because the mean of its divisors is an integer number (1512000).

Almost surely, 2^21104831 is an apocalyptic number.

21104831 is a deficient number, since it is larger than the sum of its proper divisors (3087169).

21104831 is a wasteful number, since it uses less digits than its factorization.

21104831 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1150.

The product of its (nonzero) digits is 192, while the sum is 20.

The square root of 21104831 is about 4593.9994558119. Note that the first 3 decimals coincide. The cubic root of 21104831 is about 276.3507364505.

Adding to 21104831 its reverse (13840112), we get a palindrome (34944943).

The spelling of 21104831 in words is "twenty-one million, one hundred four thousand, eight hundred thirty-one".