12558790638 has 72 divisors (see below), whose sum is σ = 29020636632. Its totient is φ = 4072963824.

The previous prime is 12558790633. The next prime is 12558790709. The reversal of 12558790638 is 83609785521.

12558790638 is a `hidden beast` number, since 1 + 25 + 587 + 9 + 0 + 6 + 38 = 666.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12558790633) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 472581 + ... + 498447.

Almost surely, 2^12558790638 is an apocalyptic number.

12558790638 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 12558790638, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (14510318316).

12558790638 is an abundant number, since it is smaller than the sum of its proper divisors (16461845994).

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

12558790638 is an frugal number, since it uses more digits than its factorization.

12558790638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25930 (or 25909 counting only the distinct ones).

The product of its (nonzero) digits is 3628800, while the sum is 54.

It can be divided in two parts, 125587 and 90638, that added together give a square (216225 = 465²).

The spelling of 12558790638 in words is "twelve billion, five hundred fifty-eight million, seven hundred ninety thousand, six hundred thirty-eight".