21000112121 has 16 divisors (see below), whose sum is σ = 23528309760. Its totient is φ = 18626469120.

The previous prime is 21000112061. The next prime is 21000112127. The reversal of 21000112121 is 12121100012.

It is not a de Polignac number, because 21000112121 - 2²⁶ = 20933003257 is a prime.

It is a super-2 number, since 2×21000112121² (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 (21000112127) 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, 108506 + ... + 231891.

It is an arithmetic number, because the mean of its divisors is an integer number (1470519360).

Almost surely, 2^21000112121 is an apocalyptic number.

It is an amenable number.

21000112121 is a deficient number, since it is larger than the sum of its proper divisors (2528197639).

21000112121 is a wasteful number, since it uses less digits than its factorization.

21000112121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 340624.

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 21000112121 its reverse (12121100012), we get a palindrome (33121212133).

The spelling of 21000112121 in words is "twenty-one billion, one hundred twelve thousand, one hundred twenty-one".