21020111131 has 16 divisors (see below), whose sum is σ = 21853301760. Its totient is φ = 20196876960.

The previous prime is 21020111111. The next prime is 21020111153. The reversal of 21020111131 is 13111102012.

It is a happy number.

It is not a de Polignac number, because 21020111131 - 2²¹ = 21018013979 is a prime.

It is a super-2 number, since 2×21020111131² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21020111111) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8149200 + ... + 8151778.

It is an arithmetic number, because the mean of its divisors is an integer number (1365831360).

Almost surely, 2^21020111131 is an apocalyptic number.

21020111131 is a deficient number, since it is larger than the sum of its proper divisors (833190629).

21020111131 is a wasteful number, since it uses less digits than its factorization.

21020111131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4386.

The product of its (nonzero) digits is 12, while the sum is 13.

Adding to 21020111131 its reverse (13111102012), we get a palindrome (34131213143).

The spelling of 21020111131 in words is "twenty-one billion, twenty million, one hundred eleven thousand, one hundred thirty-one".