21001111131 has 64 divisors (see below), whose sum is σ = 37699200000. Its totient is φ = 10042928640.

The previous prime is 21001111081. The next prime is 21001111181. The reversal of 21001111131 is 13111110012.

It is an interprime number because it is at equal distance from previous prime (21001111081) and next prime (21001111181).

It is not a de Polignac number, because 21001111131 - 2⁶ = 21001111067 is a prime.

It is a super-2 number, since 2×21001111131² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21001111181) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1110745 + ... + 1129493.

It is an arithmetic number, because the mean of its divisors is an integer number (589050000).

Almost surely, 2^21001111131 is an apocalyptic number.

21001111131 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21001111131 is a deficient number, since it is larger than the sum of its proper divisors (16698088869).

21001111131 is a wasteful number, since it uses less digits than its factorization.

21001111131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19156.

The product of its (nonzero) digits is 6, while the sum is 12.

Adding to 21001111131 its reverse (13111110012), we get a palindrome (34112221143).

The spelling of 21001111131 in words is "twenty-one billion, one million, one hundred eleven thousand, one hundred thirty-one".