66217697280 has 672 divisors, whose sum is σ = 266942767104. Its totient is φ = 14870642688.

The previous prime is 66217697269. The next prime is 66217697303. The reversal of 66217697280 is 8279671266.

66217697280 is a `hidden beast` number, since 6 + 621 + 7 + 6 + 9 + 7 + 2 + 8 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (672).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 172891969 + ... + 172892351.

Almost surely, 2^66217697280 is an apocalyptic number.

66217697280 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 66217697280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (133471383552).

66217697280 is an abundant number, since it is smaller than the sum of its proper divisors (200725069824).

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

66217697280 is a wasteful number, since it uses less digits than its factorization.

66217697280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 494 (or 467 counting only the distinct ones).

The product of its (nonzero) digits is 3048192, while the sum is 54.

The spelling of 66217697280 in words is "sixty-six billion, two hundred seventeen million, six hundred ninety-seven thousand, two hundred eighty".