21120401321 has 2 divisors, whose sum is σ = 21120401322. Its totient is φ = 21120401320.

The previous prime is 21120401303. The next prime is 21120401347. The reversal of 21120401321 is 12310402112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18403906921 + 2716494400 = 135661^2 + 52120^2 .

It is a cyclic number.

It is not a de Polignac number, because 21120401321 - 2²⁶ = 21053292457 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21120401321.

It is not a weakly prime, because it can be changed into another prime (21120401821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560200660 + 10560200661.

It is an arithmetic number, because the mean of its divisors is an integer number (10560200661).

Almost surely, 2^21120401321 is an apocalyptic number.

It is an amenable number.

21120401321 is a deficient number, since it is larger than the sum of its proper divisors (1).

21120401321 is an equidigital number, since it uses as much as digits as its factorization.

21120401321 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 96, while the sum is 17.

Adding to 21120401321 its reverse (12310402112), we get a palindrome (33430803433).

The spelling of 21120401321 in words is "twenty-one billion, one hundred twenty million, four hundred one thousand, three hundred twenty-one".