671577661440 has 1680 divisors, whose sum is σ = 2977606055952. Its totient is φ = 144473849856.

The previous prime is 671577661427. The next prime is 671577661451. The reversal of 671577661440 is 44166775176.

671577661440 is a `hidden beast` number, since 6 + 7 + 1 + 577 + 6 + 61 + 4 + 4 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1680).

It is a super-3 number, since 3×671577661440³ (a number of 36 digits) contains 333 as substring.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 39504568312 + ... + 39504568328.

Almost surely, 2^671577661440 is an apocalyptic number.

671577661440 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 671577661440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1488803027976).

671577661440 is an abundant number, since it is smaller than the sum of its proper divisors (2306028394512).

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

671577661440 is an frugal number, since it uses more digits than its factorization.

671577661440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 89 (or 34 counting only the distinct ones).

The product of its (nonzero) digits is 5927040, while the sum is 54.

The spelling of 671577661440 in words is "six hundred seventy-one billion, five hundred seventy-seven million, six hundred sixty-one thousand, four hundred forty".