64661520 has 160 divisors (see below), whose sum is σ = 249984000. Its totient is φ = 13432320.

The previous prime is 64661501. The next prime is 64661543. The reversal of 64661520 is 2516646.

It is a super-2 number, since 2×64661520² = 8362224337420800, 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 pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 16731 + ... + 20229.

It is an arithmetic number, because the mean of its divisors is an integer number (1562400).

Almost surely, 2^64661520 is an apocalyptic number.

64661520 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 64661520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (124992000).

64661520 is an abundant number, since it is smaller than the sum of its proper divisors (185322480).

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

64661520 is a wasteful number, since it uses less digits than its factorization.

64661520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3533 (or 3527 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 30.

The square root of 64661520 is about 8041.2387105470. The cubic root of 64661520 is about 401.3734453886.

The spelling of 64661520 in words is "sixty-four million, six hundred sixty-one thousand, five hundred twenty".