21264012321421 has 2 divisors, whose sum is σ = 21264012321422. Its totient is φ = 21264012321420.

The previous prime is 21264012321371. The next prime is 21264012321443. The reversal of 21264012321421 is 12412321046212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13144533040521 + 8119479280900 = 3625539^2 + 2849470^2 .

It is a cyclic number.

It is not a de Polignac number, because 21264012321421 - 2⁹ = 21264012320909 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21264012321491) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10632006160710 + 10632006160711.

It is an arithmetic number, because the mean of its divisors is an integer number (10632006160711).

Almost surely, 2^{21264012321421} is an apocalyptic number.

It is an amenable number.

21264012321421 is a deficient number, since it is larger than the sum of its proper divisors (1).

21264012321421 is an equidigital number, since it uses as much as digits as its factorization.

21264012321421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9216, while the sum is 31.

Adding to 21264012321421 its reverse (12412321046212), we get a palindrome (33676333367633).

The spelling of 21264012321421 in words is "twenty-one trillion, two hundred sixty-four billion, twelve million, three hundred twenty-one thousand, four hundred twenty-one".