21020121220100 has 36 divisors (see below), whose sum is σ = 45618145530468. Its totient is φ = 8407222224000.

The previous prime is 21020121220081. The next prime is 21020121220129. The reversal of 21020121220100 is 102212102012.

It can be written as a sum of positive squares in 6 ways, for example, as 1678491260356 + 19341629959744 = 1295566^2 + 4397912^2 .

It is a super-2 number, since 2×21020121220100² (a number of 27 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9305111 + ... + 11341310.

Almost surely, 2^{21020121220100} is an apocalyptic number.

21020121220100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21020121220100 is an abundant number, since it is smaller than the sum of its proper divisors (24598024310368).

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

21020121220100 is a wasteful number, since it uses less digits than its factorization.

21020121220100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20656616 (or 20656609 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21020121220100 its reverse (102212102012), we get a palindrome (21122333322112).

The spelling of 21020121220100 in words is "twenty-one trillion, twenty billion, one hundred twenty-one million, two hundred twenty thousand, one hundred".