21001000102120 has 32 divisors (see below), whose sum is σ = 47261111060520. Its totient is φ = 8398824782080.

The previous prime is 21001000102109. The next prime is 21001000102151. The reversal of 21001000102120 is 2120100010012.

It can be written as a sum of positive squares in 4 ways, for example, as 20548687360356 + 452312741764 = 4533066^2 + 672542^2 .

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

It is a junction number, because it is equal to n+sod(n) for n = 21001000102097 and 21001000102106.

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, 49010851 + ... + 49437490.

Almost surely, 2^{21001000102120} is an apocalyptic number.

21001000102120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21001000102120 is an abundant number, since it is smaller than the sum of its proper divisors (26260110958400).

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

21001000102120 is a wasteful number, since it uses less digits than its factorization.

21001000102120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 98453685 (or 98453681 counting only the distinct ones).

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

Adding to 21001000102120 its reverse (2120100010012), we get a palindrome (23121100112132).

The spelling of 21001000102120 in words is "twenty-one trillion, one billion, one hundred two thousand, one hundred twenty".