21002121212111 has 32 divisors (see below), whose sum is σ = 23028466083840. Its totient is φ = 19035594864000.

The previous prime is 21002121212081. The next prime is 21002121212113. The reversal of 21002121212111 is 11121212120012.

It is not a de Polignac number, because 21002121212111 - 2¹⁸ = 21002120949967 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21002121212111.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21002121212113) 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, 1328987936 + ... + 1329003738.

It is an arithmetic number, because the mean of its divisors is an integer number (719639565120).

Almost surely, 2^{21002121212111} is an apocalyptic number.

21002121212111 is a deficient number, since it is larger than the sum of its proper divisors (2026344871729).

21002121212111 is a wasteful number, since it uses less digits than its factorization.

21002121212111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18687.

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 21002121212111 its reverse (11121212120012), we get a palindrome (32123333332123).

The spelling of 21002121212111 in words is "twenty-one trillion, two billion, one hundred twenty-one million, two hundred twelve thousand, one hundred eleven".