21012020111121 has 8 divisors (see below), whose sum is σ = 30171105800640. Its totient is φ = 12930473914512.

The previous prime is 21012020111087. The next prime is 21012020111123. The reversal of 21012020111121 is 12111102021012.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21012020111121 - 2²¹ = 21012018013969 is a prime.

It is a super-2 number, since 2×21012020111121² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21012020111121.

It is not an unprimeable number, because it can be changed into a prime (21012020111123) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 269384873181 + ... + 269384873258.

It is an arithmetic number, because the mean of its divisors is an integer number (3771388225080).

Almost surely, 2^{21012020111121} is an apocalyptic number.

It is an amenable number.

21012020111121 is a deficient number, since it is larger than the sum of its proper divisors (9159085689519).

21012020111121 is a wasteful number, since it uses less digits than its factorization.

21012020111121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 538769746455.

The product of its (nonzero) digits is 16, while the sum is 15.

Adding to 21012020111121 its reverse (12111102021012), we get a palindrome (33123122132133).

The spelling of 21012020111121 in words is "twenty-one trillion, twelve billion, twenty million, one hundred eleven thousand, one hundred twenty-one".