21012020210 has 16 divisors (see below), whose sum is σ = 38277320256. Its totient is φ = 8303545008.

The previous prime is 21012020149. The next prime is 21012020221. The reversal of 21012020210 is 1202021012.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21012020191 and 21012020200.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12657014 + ... + 12658673.

It is an arithmetic number, because the mean of its divisors is an integer number (2392332516).

Almost surely, 2^21012020210 is an apocalyptic number.

21012020210 is a deficient number, since it is larger than the sum of its proper divisors (17265300046).

21012020210 is a wasteful number, since it uses less digits than its factorization.

21012020210 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25315777.

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 21012020210 its reverse (1202021012), we get a palindrome (22214041222).

The spelling of 21012020210 in words is "twenty-one billion, twelve million, twenty thousand, two hundred ten".