21051006 has 8 divisors (see below), whose sum is σ = 42102024. Its totient is φ = 7017000.

The previous prime is 21050987. The next prime is 21051011. The reversal of 21051006 is 60015012.

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

21051006 is an admirable number.

It is a super-2 number, since 2×21051006² = 886289707224072, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 1754245 + ... + 1754256.

It is an arithmetic number, because the mean of its divisors is an integer number (5262753).

Almost surely, 2^21051006 is an apocalyptic number.

21051006 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21051006 is a wasteful number, since it uses less digits than its factorization.

21051006 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3508506.

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

The square root of 21051006 is about 4588.1375306327. The cubic root of 21051006 is about 276.1156047954.

Adding to 21051006 its reverse (60015012), we get a palindrome (81066018).

It can be divided in two parts, 2 and 1051006, that multiplied together give a palindrome (2102012).

The spelling of 21051006 in words is "twenty-one million, fifty-one thousand, six".