15660128640 has 512 divisors, whose sum is σ = 57094410240. Its totient is φ = 3622993920.

The previous prime is 15660128633. The next prime is 15660128647. The reversal of 15660128640 is 4682106651.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (15660128633) and next prime (15660128647).

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15660128647) 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, 28628847 + ... + 28629393.

It is an arithmetic number, because the mean of its divisors is an integer number (111512520).

Almost surely, 2^15660128640 is an apocalyptic number.

15660128640 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 15660128640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28547205120).

15660128640 is an abundant number, since it is smaller than the sum of its proper divisors (41434281600).

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

15660128640 is a wasteful number, since it uses less digits than its factorization.

15660128640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 650 (or 638 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 39.

The spelling of 15660128640 in words is "fifteen billion, six hundred sixty million, one hundred twenty-eight thousand, six hundred forty".