130721640 has 64 divisors (see below), whose sum is σ = 448191360. Its totient is φ = 29879040.

The previous prime is 130721603. The next prime is 130721641. The reversal of 130721640 is 46127031.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 130721640.

It is not an unprimeable number, because it can be changed into a prime (130721641) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 76971 + ... + 78650.

It is an arithmetic number, because the mean of its divisors is an integer number (7002990).

Almost surely, 2^130721640 is an apocalyptic number.

130721640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

130721640 is an abundant number, since it is smaller than the sum of its proper divisors (317469720).

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

130721640 is a wasteful number, since it uses less digits than its factorization.

130721640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 155642 (or 155638 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 24.

The square root of 130721640 is about 11433.3564625616. The cubic root of 130721640 is about 507.5153270950.

Adding to 130721640 its reverse (46127031), we get a palindrome (176848671).

The spelling of 130721640 in words is "one hundred thirty million, seven hundred twenty-one thousand, six hundred forty".