66261367535280 has 240 divisors, whose sum is σ = 215239613997312. Its totient is φ = 16858862630400.

The previous prime is 66261367535261. The next prime is 66261367535281. The reversal of 66261367535280 is 8253576316266.

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (60).

It is not an unprimeable number, because it can be changed into a prime (66261367535281) 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, 14352247 + ... + 18398633.

Almost surely, 2^{66261367535280} is an apocalyptic number.

66261367535280 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 66261367535280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (107619806998656).

66261367535280 is an abundant number, since it is smaller than the sum of its proper divisors (148978246462032).

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

66261367535280 is a wasteful number, since it uses less digits than its factorization.

66261367535280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4046536 (or 4046499 counting only the distinct ones).

The product of its (nonzero) digits is 65318400, while the sum is 60.

The spelling of 66261367535280 in words is "sixty-six trillion, two hundred sixty-one billion, three hundred sixty-seven million, five hundred thirty-five thousand, two hundred eighty".