661001305536 has 672 divisors, whose sum is σ = 2275138756800. Its totient is φ = 180840038400.

The previous prime is 661001305519. The next prime is 661001305541. The reversal of 661001305536 is 635503100166.

661001305536 is a `hidden beast` number, since 6 + 6 + 100 + 13 + 0 + 5 + 536 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 661001305536.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1472163040 + ... + 1472163488.

It is an arithmetic number, because the mean of its divisors is an integer number (3385623150).

Almost surely, 2^661001305536 is an apocalyptic number.

661001305536 is a gapful number since it is divisible by the number (66) 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 661001305536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1137569378400).

661001305536 is an abundant number, since it is smaller than the sum of its proper divisors (1614137451264).

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

661001305536 is a wasteful number, since it uses less digits than its factorization.

661001305536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 845 (or 832 counting only the distinct ones).

The product of its (nonzero) digits is 48600, while the sum is 36.

The spelling of 661001305536 in words is "six hundred sixty-one billion, one million, three hundred five thousand, five hundred thirty-six".