21011112120 has 64 divisors (see below), whose sum is σ = 63486864000. Its totient is φ = 5562649728.

The previous prime is 21011112097. The next prime is 21011112131. The reversal of 21011112120 is 2121111012.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 21011112096 and 21011112105.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 613150 + ... + 646509.

It is an arithmetic number, because the mean of its divisors is an integer number (991982250).

Almost surely, 2^21011112120 is an apocalyptic number.

21011112120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21011112120 is an abundant number, since it is smaller than the sum of its proper divisors (42475751880).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21011112120 is a wasteful number, since it uses less digits than its factorization.

21011112120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1259812 (or 1259808 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 12.

Adding to 21011112120 its reverse (2121111012), we get a palindrome (23132223132).

The spelling of 21011112120 in words is "twenty-one billion, eleven million, one hundred twelve thousand, one hundred twenty".