21111001011 has 12 divisors (see below), whose sum is σ = 30495313888. Its totient is φ = 14073241104.

The previous prime is 21111000997. The next prime is 21111001057. The reversal of 21111001011 is 11010011112.

It is not a de Polignac number, because 21111001011 - 2¹⁵ = 21110968243 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21111000984 and 21111001002.

It is not an unprimeable number, because it can be changed into a prime (21111001511) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 150861 + ... + 254913.

Almost surely, 2^21111001011 is an apocalyptic number.

21111001011 is a deficient number, since it is larger than the sum of its proper divisors (9384312877).

21111001011 is a wasteful number, since it uses less digits than its factorization.

21111001011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 126602 (or 126599 counting only the distinct ones).

The product of its (nonzero) digits is 2, while the sum is 9.

Adding to 21111001011 its reverse (11010011112), we get a palindrome (32121012123).

The spelling of 21111001011 in words is "twenty-one billion, one hundred eleven million, one thousand, eleven".