21201121000 has 32 divisors (see below), whose sum is σ = 49610625480. Its totient is φ = 8480448000.

The previous prime is 21201120991. The next prime is 21201121093. The reversal of 21201121000 is 12110212.

It can be written as a sum of positive squares in 4 ways, for example, as 1908466596 + 19292654404 = 43686^2 + 138898^2 .

It is a Harshad number since it is a multiple of its sum of digits (10).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10599561 + ... + 10601560.

Almost surely, 2^21201121000 is an apocalyptic number.

21201121000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21201121000 is an abundant number, since it is smaller than the sum of its proper divisors (28409504480).

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

21201121000 is a wasteful number, since it uses less digits than its factorization.

21201121000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21201142 (or 21201128 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 21201121000 its reverse (12110212), we get a palindrome (21213231212).

The spelling of 21201121000 in words is "twenty-one billion, two hundred one million, one hundred twenty-one thousand".