664145243520 has 256 divisors, whose sum is σ = 2310583968000. Its totient is φ = 160923361280.

The previous prime is 664145243507. The next prime is 664145243527. The reversal of 664145243520 is 25342541466.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664145243527) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 48759271 + ... + 48772889.

It is an arithmetic number, because the mean of its divisors is an integer number (9025718625).

Almost surely, 2^664145243520 is an apocalyptic number.

664145243520 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 664145243520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1155291984000).

664145243520 is an abundant number, since it is smaller than the sum of its proper divisors (1646438724480).

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

664145243520 is a wasteful number, since it uses less digits than its factorization.

664145243520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15961 (or 15949 counting only the distinct ones).

The product of its (nonzero) digits is 691200, while the sum is 42.

Adding to 664145243520 its reverse (25342541466), we get a palindrome (689487784986).

The spelling of 664145243520 in words is "six hundred sixty-four billion, one hundred forty-five million, two hundred forty-three thousand, five hundred twenty".