12721991730 has 256 divisors, whose sum is σ = 37778227200. Its totient is φ = 2679505920.

The previous prime is 12721991719. The next prime is 12721991743. The reversal of 12721991730 is 3719912721.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 14913984 + ... + 14914836.

It is an arithmetic number, because the mean of its divisors is an integer number (147571200).

Almost surely, 2^12721991730 is an apocalyptic number.

12721991730 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 12721991730, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (18889113600).

12721991730 is an abundant number, since it is smaller than the sum of its proper divisors (25056235470).

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

12721991730 is a wasteful number, since it uses less digits than its factorization.

12721991730 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1009.

The product of its (nonzero) digits is 47628, while the sum is 42.

It can be divided in two parts, 12721991 and 730, that added together give a palindrome (12722721).

The spelling of 12721991730 in words is "twelve billion, seven hundred twenty-one million, nine hundred ninety-one thousand, seven hundred thirty".