21802100121 has 12 divisors (see below), whose sum is σ = 31547865648. Its totient is φ = 14508913464.

The previous prime is 21802100101. The next prime is 21802100141. The reversal of 21802100121 is 12100120812.

It is an interprime number because it is at equal distance from previous prime (21802100101) and next prime (21802100141).

It is not a de Polignac number, because 21802100121 - 2¹⁰ = 21802099097 is a prime.

It is a super-2 number, since 2×21802100121² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21802100094 and 21802100103.

It is not an unprimeable number, because it can be changed into a prime (21802100101) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2146315 + ... + 2156448.

It is an arithmetic number, because the mean of its divisors is an integer number (2628988804).

Almost surely, 2^21802100121 is an apocalyptic number.

It is an amenable number.

21802100121 is a deficient number, since it is larger than the sum of its proper divisors (9745765527).

21802100121 is a wasteful number, since it uses less digits than its factorization.

21802100121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4303332 (or 4303329 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

Adding to 21802100121 its reverse (12100120812), we get a palindrome (33902220933).

The spelling of 21802100121 in words is "twenty-one billion, eight hundred two million, one hundred thousand, one hundred twenty-one".