641661587481600 has 2475 divisors, whose sum is σ = 2779574541998177. Its totient is φ = 146256966696960.

The previous prime is 641661587481571. The next prime is 641661587481601. The reversal of 641661587481600 is 6184785166146.

The square root of 641661587481600 is 25331040.

It is a perfect power (a square), and thus also a powerful number.

641661587481600 is a `hidden beast` number, since 6 + 4 + 1 + 6 + 6 + 1 + 587 + 48 + 1 + 6 + 0 + 0 = 666.

It can be written as a sum of positive squares in only one way, i.e., 230998171493376 + 410663415988224 = 15198624^2 + 20264832^2 .

It is a Harshad number since it is a multiple of its sum of digits (63).

It is not an unprimeable number, because it can be changed into a prime (641661587481601) by changing a digit.

It is a polite number, since it can be written in 224 ways as a sum of consecutive naturals, for example, 1787358182221 + ... + 1787358182579.

Almost surely, 2^{641661587481600} is an apocalyptic number.

641661587481600 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

641661587481600 is the 25331040-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 641661587481600

641661587481600 is an abundant number, since it is smaller than the sum of its proper divisors (2137912954516577).

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

641661587481600 is an frugal number, since it uses more digits than its factorization.

641661587481600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 788 (or 376 counting only the distinct ones).

The product of its (nonzero) digits is 46448640, while the sum is 63.

The spelling of 641661587481600 in words is "six hundred forty-one trillion, six hundred sixty-one billion, five hundred eighty-seven million, four hundred eighty-one thousand, six hundred".