21002010 has 16 divisors (see below), whose sum is σ = 50404896. Its totient is φ = 5600528.

The previous prime is 21001991. The next prime is 21002039. The reversal of 21002010 is 1020012.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (6).

It is a self number, because there is not a number n which added to its sum of digits gives 21002010.

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 7 ways as a sum of consecutive naturals, for example, 350004 + ... + 350063.

It is an arithmetic number, because the mean of its divisors is an integer number (3150306).

Almost surely, 2^21002010 is an apocalyptic number.

21002010 is an abundant number, since it is smaller than the sum of its proper divisors (29402886).

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

21002010 is a wasteful number, since it uses less digits than its factorization.

21002010 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 700077.

The product of its (nonzero) digits is 4, while the sum is 6.

The square root of 21002010 is about 4582.7949986880. The cubic root of 21002010 is about 275.9012196392.

Adding to 21002010 its reverse (1020012), we get a palindrome (22022022).

The spelling of 21002010 in words is "twenty-one million, two thousand, ten".