21201121201000 has 64 divisors (see below), whose sum is σ = 53426825459280. Its totient is φ = 7828106284800.

The previous prime is 21201121200979. The next prime is 21201121201009. The reversal of 21201121201000 is 10212110212.

It can be written as a sum of positive squares in 8 ways, for example, as 954955019524 + 20246166181476 = 977218^2 + 4499574^2 .

It is a Harshad number since it is a multiple of its sum of digits (13).

It is not an unprimeable number, because it can be changed into a prime (21201121201009) 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, 815414739 + ... + 815440738.

Almost surely, 2^{21201121201000} is an apocalyptic number.

21201121201000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21201121201000 is an abundant number, since it is smaller than the sum of its proper divisors (32225704258280).

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

21201121201000 is a wasteful number, since it uses less digits than its factorization.

21201121201000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1630855511 (or 1630855497 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 21201121201000 its reverse (10212110212), we get a palindrome (21211333311212).

The spelling of 21201121201000 in words is "twenty-one trillion, two hundred one billion, one hundred twenty-one million, two hundred one thousand".