257388612066 has 80 divisors (see below), whose sum is σ = 593810050680. Its totient is φ = 83278298880.

The previous prime is 257388612059. The next prime is 257388612067. The reversal of 257388612066 is 660216883752.

257388612066 is a `hidden beast` number, since 2 + 57 + 388 + 6 + 1 + 206 + 6 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 145749096441 + 111639515625 = 381771^2 + 334125^2 .

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (257388612067) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 1210120 + ... + 1406828.

Almost surely, 2^257388612066 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 257388612066, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (296905025340).

257388612066 is an abundant number, since it is smaller than the sum of its proper divisors (336421438614).

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

257388612066 is a wasteful number, since it uses less digits than its factorization.

257388612066 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 196961 (or 196952 counting only the distinct ones).

The product of its (nonzero) digits is 5806080, while the sum is 54.

The spelling of 257388612066 in words is "two hundred fifty-seven billion, three hundred eighty-eight million, six hundred twelve thousand, sixty-six".