21000010 has 8 divisors (see below), whose sum is σ = 37800036. Its totient is φ = 8400000.

The previous prime is 20999999. The next prime is 21000037. The reversal of 21000010 is 1000012.

It can be written as a sum of positive squares in 2 ways, for example, as 19070689 + 1929321 = 4367^2 + 1389^2 .

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

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, 1049991 + ... + 1050010.

Almost surely, 2^21000010 is an apocalyptic number.

21000010 is a deficient number, since it is larger than the sum of its proper divisors (16800026).

21000010 is a wasteful number, since it uses less digits than its factorization.

21000010 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2100008.

The product of its (nonzero) digits is 2, while the sum is 4.

The square root of 21000010 is about 4582.5767860452. The cubic root of 21000010 is about 275.8924614306.

Adding to 21000010 its reverse (1000012), we get a palindrome (22000022).

The spelling of 21000010 in words is "twenty-one million, ten", and thus it is an aban number and an uban number.