666400426560 has 840 divisors, whose sum is σ = 2652921507456. Its totient is φ = 157405317120.

The previous prime is 666400426507. The next prime is 666400426561. The reversal of 666400426560 is 65624004666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (666400426561) by changing a digit.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 2988342609 + ... + 2988342831.

Almost surely, 2^666400426560 is an apocalyptic number.

666400426560 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 666400426560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1326460753728).

666400426560 is an abundant number, since it is smaller than the sum of its proper divisors (1986521080896).

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

666400426560 is a wasteful number, since it uses less digits than its factorization.

666400426560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 533 (or 291 counting only the distinct ones).

The product of its (nonzero) digits is 1244160, while the sum is 45.

The spelling of 666400426560 in words is "six hundred sixty-six billion, four hundred million, four hundred twenty-six thousand, five hundred sixty".