661583946240 has 1440 divisors, whose sum is σ = 2887797204864. Its totient is φ = 141893959680.

The previous prime is 661583946211. The next prime is 661583946263. The reversal of 661583946240 is 42649385166.

661583946240 is a `hidden beast` number, since 6 + 6 + 1 + 5 + 8 + 3 + 9 + 4 + 624 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1440).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 1998742875 + ... + 1998743205.

Almost surely, 2^661583946240 is an apocalyptic number.

661583946240 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 661583946240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1443898602432).

661583946240 is an abundant number, since it is smaller than the sum of its proper divisors (2226213258624).

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

661583946240 is an frugal number, since it uses more digits than its factorization.

661583946240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 402 (or 365 counting only the distinct ones).

The product of its (nonzero) digits is 7464960, while the sum is 54.

The spelling of 661583946240 in words is "six hundred sixty-one billion, five hundred eighty-three million, nine hundred forty-six thousand, two hundred forty".