1664136257256 has 384 divisors, whose sum is σ = 5087475993600. Its totient is φ = 487071728640.

The previous prime is 1664136257243. The next prime is 1664136257261. The reversal of 1664136257256 is 6527526314661.

1664136257256 is a `hidden beast` number, since 1 + 6 + 6 + 4 + 1 + 3 + 62 + 572 + 5 + 6 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1291028260 + ... + 1291029548.

It is an arithmetic number, because the mean of its divisors is an integer number (13248635400).

Almost surely, 2^{1664136257256} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1664136257256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2543737996800).

1664136257256 is an abundant number, since it is smaller than the sum of its proper divisors (3423339736344).

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

1664136257256 is a wasteful number, since it uses less digits than its factorization.

1664136257256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1749 (or 1742 counting only the distinct ones).

The product of its digits is 10886400, while the sum is 54.

The spelling of 1664136257256 in words is "one trillion, six hundred sixty-four billion, one hundred thirty-six million, two hundred fifty-seven thousand, two hundred fifty-six".