21005106 has 32 divisors (see below), whose sum is σ = 44193600. Its totient is φ = 6646080.

The previous prime is 21005087. The next prime is 21005111. The reversal of 21005106 is 60150012.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9625 + ... + 11603.

It is an arithmetic number, because the mean of its divisors is an integer number (1381050).

Almost surely, 2^21005106 is an apocalyptic number.

21005106 is an abundant number, since it is smaller than the sum of its proper divisors (23188494).

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

21005106 is a wasteful number, since it uses less digits than its factorization.

21005106 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2074.

The product of its (nonzero) digits is 60, while the sum is 15.

The square root of 21005106 is about 4583.1327713694. The cubic root of 21005106 is about 275.9147762497.

Adding to 21005106 its reverse (60150012), we get a palindrome (81155118).

The spelling of 21005106 in words is "twenty-one million, five thousand, one hundred six".