1264005866640 has 320 divisors, whose sum is σ = 4621237079040. Its totient is φ = 282451691520.

The previous prime is 1264005866639. The next prime is 1264005866647. The reversal of 1264005866640 is 466685004621.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 1264005866640.

It is not an unprimeable number, because it can be changed into a prime (1264005866647) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1515387 + ... + 2196453.

It is an arithmetic number, because the mean of its divisors is an integer number (14441365872).

Almost surely, 2^{1264005866640} is an apocalyptic number.

1264005866640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1264005866640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2310618539520).

1264005866640 is an abundant number, since it is smaller than the sum of its proper divisors (3357231212400).

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

1264005866640 is a wasteful number, since it uses less digits than its factorization.

1264005866640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 681150 (or 681144 counting only the distinct ones).

The product of its (nonzero) digits is 1658880, while the sum is 48.

The spelling of 1264005866640 in words is "one trillion, two hundred sixty-four billion, five million, eight hundred sixty-six thousand, six hundred forty".