21020212011 has 32 divisors (see below), whose sum is σ = 28565849088. Its totient is φ = 13747190400.

The previous prime is 21020211983. The next prime is 21020212019. The reversal of 21020212011 is 11021202012.

It is not a de Polignac number, because 21020212011 - 2²² = 21016017707 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21020212019) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 24642261 + ... + 24643113.

It is an arithmetic number, because the mean of its divisors is an integer number (892682784).

Almost surely, 2^21020212011 is an apocalyptic number.

21020212011 is a deficient number, since it is larger than the sum of its proper divisors (7545637077).

21020212011 is a wasteful number, since it uses less digits than its factorization.

21020212011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1611.

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21020212011 its reverse (11021202012), we get a palindrome (32041414023).

Subtracting from 21020212011 its reverse (11021202012), we obtain a palindrome (9999009999).

The spelling of 21020212011 in words is "twenty-one billion, twenty million, two hundred twelve thousand, eleven".