201221202121020 has 72 divisors (see below), whose sum is σ = 610372263271680. Its totient is φ = 53658874396800.

The previous prime is 201221202121001. The next prime is 201221202121039. The reversal of 201221202121020 is 20121202122102.

It is a happy number.

201221202121020 is a `hidden beast` number, since 201 + 2 + 212 + 0 + 21 + 210 + 20 = 666.

It is an interprime number because it is at equal distance from previous prime (201221202121001) and next prime (201221202121039).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 201221202120984 and 201221202121002.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 118306786 + ... + 119995574.

It is an arithmetic number, because the mean of its divisors is an integer number (8477392545440).

Almost surely, 2^{201221202121020} is an apocalyptic number.

201221202121020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

201221202121020 is an abundant number, since it is smaller than the sum of its proper divisors (409151061150660).

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

201221202121020 is a wasteful number, since it uses less digits than its factorization.

201221202121020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2350755 (or 2350750 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 201221202121020 its reverse (20121202122102), we get a palindrome (221342404243122).

The spelling of 201221202121020 in words is "two hundred one trillion, two hundred twenty-one billion, two hundred two million, one hundred twenty-one thousand, twenty".