2578136640 has 112 divisors (see below), whose sum is σ = 8206313280. Its totient is φ = 685762560.

The previous prime is 2578136599. The next prime is 2578136647. The reversal of 2578136640 is 466318752.

It is a hoax number, since the sum of its digits (42) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 2578136592 and 2578136601.

It is not an unprimeable number, because it can be changed into a prime (2578136647) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 400971 + ... + 407349.

Almost surely, 2^2578136640 is an apocalyptic number.

2578136640 is a gapful number since it is divisible by the number (20) 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 2578136640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4103156640).

2578136640 is an abundant number, since it is smaller than the sum of its proper divisors (5628176640).

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

2578136640 is a wasteful number, since it uses less digits than its factorization.

2578136640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6820 (or 6810 counting only the distinct ones).

The product of its (nonzero) digits is 241920, while the sum is 42.

The square root of 2578136640 is about 50775.3546516418. The cubic root of 2578136640 is about 1371.2037017220.

The spelling of 2578136640 in words is "two billion, five hundred seventy-eight million, one hundred thirty-six thousand, six hundred forty".