25545355615566 has 40 divisors (see below), whose sum is σ = 57248177325240. Its totient is φ = 8513979293232.

The previous prime is 25545355615541. The next prime is 25545355615567. The reversal of 25545355615566 is 66551655354552.

It is a happy number.

25545355615566 is a `hidden beast` number, since 2 + 5 + 5 + 4 + 5 + 3 + 5 + 5 + 61 + 5 + 566 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25545355615567) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 9333556 + ... + 11756103.

It is an arithmetic number, because the mean of its divisors is an integer number (1431204433131).

Almost surely, 2^{25545355615566} is an apocalyptic number.

25545355615566 is an abundant number, since it is smaller than the sum of its proper divisors (31702821709674).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

25545355615566 is a wasteful number, since it uses less digits than its factorization.

25545355615566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21097150 (or 21097141 counting only the distinct ones).

The product of its digits is 405000000, while the sum is 63.

The spelling of 25545355615566 in words is "twenty-five trillion, five hundred forty-five billion, three hundred fifty-five million, six hundred fifteen thousand, five hundred sixty-six".