21012121101321 has 24 divisors (see below), whose sum is σ = 35255310144704. Its totient is φ = 11810091483360.

The previous prime is 21012121101299. The next prime is 21012121101371. The reversal of 21012121101321 is 12310112121012.

It is a happy number.

21012121101321 is a `hidden beast` number, since 2 + 10 + 121 + 211 + 0 + 1 + 321 = 666.

It is not a de Polignac number, because 21012121101321 - 2⁵ = 21012121101289 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21012121101294 and 21012121101303.

It is not an unprimeable number, because it can be changed into a prime (21012121101371) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2733813631 + ... + 2733821316.

Almost surely, 2^{21012121101321} is an apocalyptic number.

21012121101321 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21012121101321 is a deficient number, since it is larger than the sum of its proper divisors (14243189043383).

21012121101321 is a wasteful number, since it uses less digits than its factorization.

21012121101321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5467635021 (or 5467635018 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 18.

Adding to 21012121101321 its reverse (12310112121012), we get a palindrome (33322233222333).

The spelling of 21012121101321 in words is "twenty-one trillion, twelve billion, one hundred twenty-one million, one hundred one thousand, three hundred twenty-one".