21121002001000 has 64 divisors (see below), whose sum is σ = 53916157863360. Its totient is φ = 7680364360000.

The previous prime is 21121002000961. The next prime is 21121002001007. The reversal of 21121002001000 is 10020012112.

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

It is not an unprimeable number, because it can be changed into a prime (21121002001007) 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, 960034546 + ... + 960056545.

It is an arithmetic number, because the mean of its divisors is an integer number (842439966615).

Almost surely, 2^{21121002001000} is an apocalyptic number.

21121002001000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21121002001000 is an abundant number, since it is smaller than the sum of its proper divisors (32795155862360).

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

21121002001000 is a wasteful number, since it uses less digits than its factorization.

21121002001000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1920091123 (or 1920091109 counting only the distinct ones).

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

Adding to 21121002001000 its reverse (10020012112), we get a palindrome (21131022013112).

The spelling of 21121002001000 in words is "twenty-one trillion, one hundred twenty-one billion, two million, one thousand".