661541199264 has 1152 divisors, whose sum is σ = 2386166065920. Its totient is φ = 171196416000.

The previous prime is 661541199229. The next prime is 661541199307. The reversal of 661541199264 is 462991145166.

661541199264 is a `hidden beast` number, since 6 + 6 + 1 + 541 + 1 + 9 + 92 + 6 + 4 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 661541199264.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 3823937482 + ... + 3823937654.

It is an arithmetic number, because the mean of its divisors is an integer number (2071324710).

Almost surely, 2^661541199264 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661541199264, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1193083032960).

661541199264 is an abundant number, since it is smaller than the sum of its proper divisors (1724624866656).

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

661541199264 is a wasteful number, since it uses less digits than its factorization.

661541199264 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 374 (or 363 counting only the distinct ones).

The product of its digits is 2799360, while the sum is 54.

The spelling of 661541199264 in words is "six hundred sixty-one billion, five hundred forty-one million, one hundred ninety-nine thousand, two hundred sixty-four".