21112121000 has 32 divisors (see below), whose sum is σ = 49402365480. Its totient is φ = 8444848000.

The previous prime is 21112120979. The next prime is 21112121003. The reversal of 21112121000 is 12121112.

It can be written as a sum of positive squares in 4 ways, for example, as 4007143204 + 17104977796 = 63302^2 + 130786^2 .

It is not an unprimeable number, because it can be changed into a prime (21112121003) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10555061 + ... + 10557060.

Almost surely, 2^21112121000 is an apocalyptic number.

21112121000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21112121000 is an abundant number, since it is smaller than the sum of its proper divisors (28290244480).

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

21112121000 is a wasteful number, since it uses less digits than its factorization.

21112121000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21112142 (or 21112128 counting only the distinct ones).

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

Adding to 21112121000 its reverse (12121112), we get a palindrome (21124242112).

The spelling of 21112121000 in words is "twenty-one billion, one hundred twelve million, one hundred twenty-one thousand".