21052006 has 8 divisors (see below), whose sum is σ = 31625784. Its totient is φ = 10510080.

The previous prime is 21051991. The next prime is 21052039. The reversal of 21052006 is 60025012.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 6235 + ... + 8998.

It is an arithmetic number, because the mean of its divisors is an integer number (3953223).

Almost surely, 2^21052006 is an apocalyptic number.

21052006 is a deficient number, since it is larger than the sum of its proper divisors (10573778).

21052006 is a wasteful number, since it uses less digits than its factorization.

21052006 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15926.

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 21052006 is about 4588.2465060195. The cubic root of 21052006 is about 276.1199768941.

Adding to 21052006 its reverse (60025012), we get a palindrome (81077018).

It can be divided in two parts, 2 and 1052006, that multiplied together give a palindrome (2104012).

The spelling of 21052006 in words is "twenty-one million, fifty-two thousand, six".