25320521457821 has 2 divisors, whose sum is σ = 25320521457822. Its totient is φ = 25320521457820.

The previous prime is 25320521457817. The next prime is 25320521457851. The reversal of 25320521457821 is 12875412502352.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 23107835457721 + 2212686000100 = 4807061^2 + 1487510^2 .

It is a cyclic number.

It is not a de Polignac number, because 25320521457821 - 2² = 25320521457817 is a prime.

It is a super-2 number, since 2×25320521457821² (a number of 28 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25320521457851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12660260728910 + 12660260728911.

It is an arithmetic number, because the mean of its divisors is an integer number (12660260728911).

Almost surely, 2^{25320521457821} is an apocalyptic number.

It is an amenable number.

25320521457821 is a deficient number, since it is larger than the sum of its proper divisors (1).

25320521457821 is an equidigital number, since it uses as much as digits as its factorization.

25320521457821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1344000, while the sum is 47.

The spelling of 25320521457821 in words is "twenty-five trillion, three hundred twenty billion, five hundred twenty-one million, four hundred fifty-seven thousand, eight hundred twenty-one".