21001210111 has 32 divisors (see below), whose sum is σ = 25117678080. Its totient is φ = 17179344000.

The previous prime is 21001210051. The next prime is 21001210127. The reversal of 21001210111 is 11101210012.

It is not a de Polignac number, because 21001210111 - 2¹⁵ = 21001177343 is a prime.

It is a super-2 number, since 2×21001210111² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001210171) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 7364836 + ... + 7367686.

It is an arithmetic number, because the mean of its divisors is an integer number (784927440).

Almost surely, 2^21001210111 is an apocalyptic number.

21001210111 is a deficient number, since it is larger than the sum of its proper divisors (4116467969).

21001210111 is a wasteful number, since it uses less digits than its factorization.

21001210111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3295.

The product of its (nonzero) digits is 4, while the sum is 10.

Adding to 21001210111 its reverse (11101210012), we get a palindrome (32102420123).

Subtracting from 21001210111 its reverse (11101210012), we obtain a palindrome (9900000099).

The spelling of 21001210111 in words is "twenty-one billion, one million, two hundred ten thousand, one hundred eleven".