21325129215881 has 2 divisors, whose sum is σ = 21325129215882. Its totient is φ = 21325129215880.

The previous prime is 21325129215833. The next prime is 21325129215883. The reversal of 21325129215881 is 18851292152312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16255048380025 + 5070080835856 = 4031755^2 + 2251684^2 .

It is a cyclic number.

It is not a de Polignac number, because 21325129215881 - 2³⁸ = 21050251308937 is a prime.

It is a super-2 number, since 2×21325129215881² (a number of 27 digits) contains 22 as substring.

Together with 21325129215883, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21325129215883) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10662564607940 + 10662564607941.

It is an arithmetic number, because the mean of its divisors is an integer number (10662564607941).

Almost surely, 2^{21325129215881} is an apocalyptic number.

It is an amenable number.

21325129215881 is a deficient number, since it is larger than the sum of its proper divisors (1).

21325129215881 is an equidigital number, since it uses as much as digits as its factorization.

21325129215881 is an evil number, because the sum of its binary digits is even.

The product of its digits is 691200, while the sum is 50.

The spelling of 21325129215881 in words is "twenty-one trillion, three hundred twenty-five billion, one hundred twenty-nine million, two hundred fifteen thousand, eight hundred eighty-one".