21002106 has 32 divisors (see below), whose sum is σ = 46820160. Its totient is φ = 6241536.

The previous prime is 21002101. The next prime is 21002129. The reversal of 21002106 is 60120012.

It is a junction number, because it is equal to n+sod(n) for n = 21002091 and 21002100.

It is not an unprimeable number, because it can be changed into a prime (21002101) 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 in 15 ways as a sum of consecutive naturals, for example, 3481 + ... + 7356.

It is an arithmetic number, because the mean of its divisors is an integer number (1463130).

Almost surely, 2^21002106 is an apocalyptic number.

21002106 is an abundant number, since it is smaller than the sum of its proper divisors (25818054).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21002106 is a wasteful number, since it uses less digits than its factorization.

21002106 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10878.

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 21002106 is about 4582.8054726335. The cubic root of 21002106 is about 275.9016400192.

Adding to 21002106 its reverse (60120012), we get a palindrome (81122118).

The spelling of 21002106 in words is "twenty-one million, two thousand, one hundred six".