15661375488 has 448 divisors, whose sum is σ = 52184442240. Its totient is φ = 4600627200.

The previous prime is 15661375469. The next prime is 15661375519. The reversal of 15661375488 is 88457316651.

It is a happy number.

15661375488 is a `hidden beast` number, since 1 + 5 + 6 + 61 + 37 + 548 + 8 = 666.

It is a super-2 number, since 2×15661375488² (a number of 21 digits) contains 22 as substring.

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

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 99753906 + ... + 99754062.

It is an arithmetic number, because the mean of its divisors is an integer number (116483130).

Almost surely, 2^15661375488 is an apocalyptic number.

15661375488 is a gapful number since it is divisible by the number (18) 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 15661375488, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26092221120).

15661375488 is an abundant number, since it is smaller than the sum of its proper divisors (36523066752).

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

15661375488 is a wasteful number, since it uses less digits than its factorization.

15661375488 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 244 (or 214 counting only the distinct ones).

The product of its digits is 4838400, while the sum is 54.

The spelling of 15661375488 in words is "fifteen billion, six hundred sixty-one million, three hundred seventy-five thousand, four hundred eighty-eight".