25122781 has 2 divisors, whose sum is σ = 25122782. Its totient is φ = 25122780.

The previous prime is 25122767. The next prime is 25122809. The reversal of 25122781 is 18722152.

It is an a-pointer prime, because the next prime (25122809) can be obtained adding 25122781 to its sum of digits (28).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 23609881 + 1512900 = 4859^2 + 1230^2 .

It is a cyclic number.

It is not a de Polignac number, because 25122781 - 2¹⁷ = 24991709 is a prime.

It is a super-2 number, since 2×25122781² = 1262308250347922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25122751) 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, 12561390 + 12561391.

It is an arithmetic number, because the mean of its divisors is an integer number (12561391).

Almost surely, 2^25122781 is an apocalyptic number.

It is an amenable number.

25122781 is a deficient number, since it is larger than the sum of its proper divisors (1).

25122781 is an equidigital number, since it uses as much as digits as its factorization.

25122781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2240, while the sum is 28.

The square root of 25122781 is about 5012.2630617317. The cubic root of 25122781 is about 292.8796774026.

It can be divided in two parts, 251 and 22781, that added together give a palindrome (23032).

The spelling of 25122781 in words is "twenty-five million, one hundred twenty-two thousand, seven hundred eighty-one".