25406564461549 has 4 divisors (see below), whose sum is σ = 25553423215836. Its totient is φ = 25259705707264.

The previous prime is 25406564461507. The next prime is 25406564461591. The reversal of 25406564461549 is 94516446560452.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (25406564461507) and next prime (25406564461591).

It can be written as a sum of positive squares in 2 ways, for example, as 18259443433449 + 7147121028100 = 4273107^2 + 2673410^2 .

It is a cyclic number.

It is not a de Polignac number, because 25406564461549 - 2²³ = 25406556072941 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25406564461249) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (31) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 73429376884 + ... + 73429377229.

It is an arithmetic number, because the mean of its divisors is an integer number (6388355803959).

Almost surely, 2^{25406564461549} is an apocalyptic number.

It is an amenable number.

25406564461549 is a deficient number, since it is larger than the sum of its proper divisors (146858754287).

25406564461549 is a wasteful number, since it uses less digits than its factorization.

25406564461549 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 146858754286.

The product of its (nonzero) digits is 124416000, while the sum is 61.

The spelling of 25406564461549 in words is "twenty-five trillion, four hundred six billion, five hundred sixty-four million, four hundred sixty-one thousand, five hundred forty-nine".