660731520 has 256 divisors, whose sum is σ = 2305428480. Its totient is φ = 160235520.

The previous prime is 660731497. The next prime is 660731531. The reversal of 660731520 is 25137066.

It is a super-2 number, since 2×660731520² = 873132283043020800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

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, 1011514 + ... + 1012166.

It is an arithmetic number, because the mean of its divisors is an integer number (9005580).

Almost surely, 2^660731520 is an apocalyptic number.

660731520 is a gapful number since it is divisible by the number (60) 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 660731520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1152714240).

660731520 is an abundant number, since it is smaller than the sum of its proper divisors (1644696960).

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

660731520 is a wasteful number, since it uses less digits than its factorization.

660731520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 723 (or 711 counting only the distinct ones).

The product of its (nonzero) digits is 7560, while the sum is 30.

The square root of 660731520 is about 25704.6984032103. The cubic root of 660731520 is about 870.9803191883.

Adding to 660731520 its reverse (25137066), we get a palindrome (685868586).

The spelling of 660731520 in words is "six hundred sixty million, seven hundred thirty-one thousand, five hundred twenty".