20201220100021 has 16 divisors (see below), whose sum is σ = 20986208066560. Its totient is φ = 19424810050560.

The previous prime is 20201220099971. The next prime is 20201220100043. The reversal of 20201220100021 is 12000102210202.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 20201220100021 - 2²⁷ = 20201085882293 is a prime.

It is a super-2 number, since 2×20201220100021² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20201220099974 and 20201220100010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20201220107021) 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, 2923456 + ... + 6996358.

It is an arithmetic number, because the mean of its divisors is an integer number (1311638004160).

Almost surely, 2^{20201220100021} is an apocalyptic number.

It is an amenable number.

20201220100021 is a deficient number, since it is larger than the sum of its proper divisors (784987966539).

20201220100021 is a wasteful number, since it uses less digits than its factorization.

20201220100021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4073956.

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 20201220100021 its reverse (12000102210202), we get a palindrome (32201322310223).

The spelling of 20201220100021 in words is "twenty trillion, two hundred one billion, two hundred twenty million, one hundred thousand, twenty-one".