21111121001000 has 32 divisors (see below), whose sum is σ = 49400023144680. Its totient is φ = 8444448400000.

The previous prime is 21111121000993. The next prime is 21111121001041. The reversal of 21111121001000 is 10012111112.

It can be written as a sum of positive squares in 4 ways, for example, as 2316173522404 + 18794947478596 = 1521898^2 + 4335314^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10555559501 + ... + 10555561500.

Almost surely, 2^{21111121001000} is an apocalyptic number.

21111121001000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21111121001000 is an abundant number, since it is smaller than the sum of its proper divisors (28288902143680).

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

21111121001000 is a wasteful number, since it uses less digits than its factorization.

21111121001000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21111121022 (or 21111121008 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 11.

Adding to 21111121001000 its reverse (10012111112), we get a palindrome (21121133112112).

The spelling of 21111121001000 in words is "twenty-one trillion, one hundred eleven billion, one hundred twenty-one million, one thousand".