21105007 has 32 divisors (see below), whose sum is σ = 29113344. Its totient is φ = 14784000.

The previous prime is 21104999. The next prime is 21105013. The reversal of 21105007 is 70050112.

It is not a de Polignac number, because 21105007 - 2³ = 21104999 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21105047) 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 31 ways as a sum of consecutive naturals, for example, 29757 + ... + 30457.

It is an arithmetic number, because the mean of its divisors is an integer number (909792).

Almost surely, 2^21105007 is an apocalyptic number.

21105007 is a deficient number, since it is larger than the sum of its proper divisors (8008337).

21105007 is a wasteful number, since it uses less digits than its factorization.

21105007 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 759.

The product of its (nonzero) digits is 70, while the sum is 16.

The square root of 21105007 is about 4594.0186111943. The cubic root of 21105007 is about 276.3515046410.

Adding to 21105007 its reverse (70050112), we get a palindrome (91155119).

It can be divided in two parts, 2110 and 5007, that added together give a palindrome (7117).

The spelling of 21105007 in words is "twenty-one million, one hundred five thousand, seven".