25164355721 has 2 divisors, whose sum is σ = 25164355722. Its totient is φ = 25164355720.

The previous prime is 25164355633. The next prime is 25164355807. The reversal of 25164355721 is 12755346152.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 24647430025 + 516925696 = 156995^2 + 22736^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-25164355721 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (25164357721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12582177860 + 12582177861.

It is an arithmetic number, because the mean of its divisors is an integer number (12582177861).

Almost surely, 2^25164355721 is an apocalyptic number.

It is an amenable number.

25164355721 is a deficient number, since it is larger than the sum of its proper divisors (1).

25164355721 is an equidigital number, since it uses as much as digits as its factorization.

25164355721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 252000, while the sum is 41.

The spelling of 25164355721 in words is "twenty-five billion, one hundred sixty-four million, three hundred fifty-five thousand, seven hundred twenty-one".