21020100121 has 16 divisors (see below), whose sum is σ = 22564080000. Its totient is φ = 19523161728.

The previous prime is 21020100119. The next prime is 21020100151. The reversal of 21020100121 is 12100102012.

It is a cyclic number.

It is not a de Polignac number, because 21020100121 - 2¹ = 21020100119 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21020100098 and 21020100107.

It is not an unprimeable number, because it can be changed into a prime (21020100151) 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, 186255 + ... + 277003.

It is an arithmetic number, because the mean of its divisors is an integer number (1410255000).

Almost surely, 2^21020100121 is an apocalyptic number.

It is an amenable number.

21020100121 is a deficient number, since it is larger than the sum of its proper divisors (1543979879).

21020100121 is a wasteful number, since it uses less digits than its factorization.

21020100121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91008.

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

Adding to 21020100121 its reverse (12100102012), we get a palindrome (33120202133).

The spelling of 21020100121 in words is "twenty-one billion, twenty million, one hundred thousand, one hundred twenty-one".