12721661550 has 480 divisors, whose sum is σ = 40018188672. Its totient is φ = 2976030720.

The previous prime is 12721661543. The next prime is 12721661551. The reversal of 12721661550 is 5516612721.

12721661550 is a `hidden beast` number, since 1 + 27 + 2 + 16 + 615 + 5 + 0 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12721661551) by changing a digit.

It is a polite number, since it can be written in 239 ways as a sum of consecutive naturals, for example, 131151102 + ... + 131151198.

Almost surely, 2^12721661550 is an apocalyptic number.

12721661550 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 12721661550, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20009094336).

12721661550 is an abundant number, since it is smaller than the sum of its proper divisors (27296527122).

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

12721661550 is a wasteful number, since it uses less digits than its factorization.

12721661550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 234 (or 220 counting only the distinct ones).

The product of its (nonzero) digits is 25200, while the sum is 36.

The spelling of 12721661550 in words is "twelve billion, seven hundred twenty-one million, six hundred sixty-one thousand, five hundred fifty".