664561001478 has 96 divisors (see below), whose sum is σ = 1521348337152. Its totient is φ = 191912846400.

The previous prime is 664561001453. The next prime is 664561001479. The reversal of 664561001478 is 874100165466.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664561001479) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 9426576 + ... + 9496812.

It is an arithmetic number, because the mean of its divisors is an integer number (15847378512).

Almost surely, 2^664561001478 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 664561001478, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (760674168576).

664561001478 is an abundant number, since it is smaller than the sum of its proper divisors (856787335674).

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

664561001478 is a wasteful number, since it uses less digits than its factorization.

664561001478 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70570 (or 70547 counting only the distinct ones).

The product of its (nonzero) digits is 967680, while the sum is 48.

The spelling of 664561001478 in words is "six hundred sixty-four billion, five hundred sixty-one million, one thousand, four hundred seventy-eight".