25543681 has 2 divisors, whose sum is σ = 25543682. Its totient is φ = 25543680.

The previous prime is 25543669. The next prime is 25543699. The reversal of 25543681 is 18634552.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17472400 + 8071281 = 4180^2 + 2841^2 .

It is a cyclic number.

It is not a de Polignac number, because 25543681 - 2¹⁵ = 25510913 is a prime.

It is a super-2 number, since 2×25543681² = 1304959278059522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (25543621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12771840 + 12771841.

It is an arithmetic number, because the mean of its divisors is an integer number (12771841).

Almost surely, 2^25543681 is an apocalyptic number.

It is an amenable number.

25543681 is a deficient number, since it is larger than the sum of its proper divisors (1).

25543681 is an equidigital number, since it uses as much as digits as its factorization.

25543681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 28800, while the sum is 34.

The square root of 25543681 is about 5054.0756820610. The cubic root of 25543681 is about 294.5062351973.

The spelling of 25543681 in words is "twenty-five million, five hundred forty-three thousand, six hundred eighty-one".