25561031 has 2 divisors, whose sum is σ = 25561032. Its totient is φ = 25561030.

The previous prime is 25561009. The next prime is 25561033. The reversal of 25561031 is 13016552.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 25561031 - 2¹⁸ = 25298887 is a prime.

It is a super-2 number, since 2×25561031² = 1306732611565922, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 25561033, it forms a pair of twin primes.

It is a Chen prime.

It is a zygodrome in base 2.

It is a junction number, because it is equal to n+sod(n) for n = 25560988 and 25561006.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25561033) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12780515 + 12780516.

It is an arithmetic number, because the mean of its divisors is an integer number (12780516).

Almost surely, 2^25561031 is an apocalyptic number.

25561031 is a deficient number, since it is larger than the sum of its proper divisors (1).

25561031 is an equidigital number, since it uses as much as digits as its factorization.

25561031 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 900, while the sum is 23.

The square root of 25561031 is about 5055.7918272017. The cubic root of 25561031 is about 294.5728991305.

Adding to 25561031 its reverse (13016552), we get a palindrome (38577583).

The spelling of 25561031 in words is "twenty-five million, five hundred sixty-one thousand, thirty-one".