21121111010 has 16 divisors (see below), whose sum is σ = 38022075000. Its totient is φ = 8447538816.

The previous prime is 21121110977. The next prime is 21121111019. The reversal of 21121111010 is 1011112112.

It can be written as a sum of positive squares in 4 ways, for example, as 7588674769 + 13532436241 = 87113^2 + 116329^2 .

It is a super-2 number, since 2×21121111010² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21121110982 and 21121111000.

It is not an unprimeable number, because it can be changed into a prime (21121111019) 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 7 ways as a sum of consecutive naturals, for example, 10835 + ... + 205814.

Almost surely, 2^21121111010 is an apocalyptic number.

21121111010 is a deficient number, since it is larger than the sum of its proper divisors (16900963990).

21121111010 is a wasteful number, since it uses less digits than its factorization.

21121111010 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 226405.

The product of its (nonzero) digits is 4, while the sum is 11.

Adding to 21121111010 its reverse (1011112112), we get a palindrome (22132223122).

The spelling of 21121111010 in words is "twenty-one billion, one hundred twenty-one million, one hundred eleven thousand, ten".