1531998720 has 720 divisors, whose sum is σ = 6549491520. Its totient is φ = 329269248.

The previous prime is 1531998691. The next prime is 1531998739. The reversal of 1531998720 is 278991351.

1531998720 is a `hidden beast` number, since 1 + 531 + 9 + 98 + 7 + 20 = 666.

It is a tau number, because it is divible by the number of its divisors (720).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 25966051 + ... + 25966109.

It is an arithmetic number, because the mean of its divisors is an integer number (9096516).

Almost surely, 2^1531998720 is an apocalyptic number.

1531998720 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 1531998720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3274745760).

1531998720 is an abundant number, since it is smaller than the sum of its proper divisors (5017492800).

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

1531998720 is a wasteful number, since it uses less digits than its factorization.

1531998720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 125 (or 99 counting only the distinct ones).

The product of its (nonzero) digits is 136080, while the sum is 45.

The square root of 1531998720 is about 39140.7552303223. The cubic root of 1531998720 is about 1152.7969023150.

The spelling of 1531998720 in words is "one billion, five hundred thirty-one million, nine hundred ninety-eight thousand, seven hundred twenty".