21121221010020 has 48 divisors (see below), whose sum is σ = 60141781869120. Its totient is φ = 5536862455936.

The previous prime is 21121221009949. The next prime is 21121221010111. The reversal of 21121221010020 is 2001012212112.

It is a super-2 number, since 2×21121221010020² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2983219767 + ... + 2983226846.

It is an arithmetic number, because the mean of its divisors is an integer number (1252953788940).

Almost surely, 2^{21121221010020} is an apocalyptic number.

21121221010020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21121221010020 is an abundant number, since it is smaller than the sum of its proper divisors (39020560859100).

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

21121221010020 is a wasteful number, since it uses less digits than its factorization.

21121221010020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5966446684 (or 5966446682 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21121221010020 its reverse (2001012212112), we get a palindrome (23122233222132).

The spelling of 21121221010020 in words is "twenty-one trillion, one hundred twenty-one billion, two hundred twenty-one million, ten thousand, twenty".