25533163681 has 3 divisors (see below), whose sum is σ = 25533323473. Its totient is φ = 25533003890.

The previous prime is 25533163597. The next prime is 25533163687. The reversal of 25533163681 is 18636133552.

It is a happy number.

The square root of 25533163681 is 159791.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 25533163681 - 2⁹ = 25533163169 is a prime.

It is a super-2 number, since 2×25533163681² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25533163687) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 79896 + ... + 239686.

Almost surely, 2^25533163681 is an apocalyptic number.

25533163681 is the 159791-st square number.

25533163681 is the 79896-th centered octagonal number.

It is an amenable number.

25533163681 is a deficient number, since it is larger than the sum of its proper divisors (159792).

25533163681 is an frugal number, since it uses more digits than its factorization.

25533163681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 319582 (or 159791 counting only the distinct ones).

The product of its digits is 388800, while the sum is 43.

The spelling of 25533163681 in words is "twenty-five billion, five hundred thirty-three million, one hundred sixty-three thousand, six hundred eighty-one".