661540171284 has 144 divisors (see below), whose sum is σ = 1710724055040. Its totient is φ = 215485358400.

The previous prime is 661540171277. The next prime is 661540171319. The reversal of 661540171284 is 482171045166.

661540171284 is a `hidden beast` number, since 6 + 6 + 1 + 540 + 17 + 12 + 84 = 666.

661540171284 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 339076509 + ... + 339078459.

It is an arithmetic number, because the mean of its divisors is an integer number (11880028160).

Almost surely, 2^661540171284 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 661540171284, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (855362027520).

661540171284 is an abundant number, since it is smaller than the sum of its proper divisors (1049183883756).

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

661540171284 is a wasteful number, since it uses less digits than its factorization.

661540171284 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2890 (or 2885 counting only the distinct ones).

The product of its (nonzero) digits is 322560, while the sum is 45.

The spelling of 661540171284 in words is "six hundred sixty-one billion, five hundred forty million, one hundred seventy-one thousand, two hundred eighty-four".