66581277489792 has 768 divisors, whose sum is σ = 218418428067840. Its totient is φ = 19321307136000.

The previous prime is 66581277489707. The next prime is 66581277489803. The reversal of 66581277489792 is 29798477218566.

66581277489792 is a `hidden beast` number, since 6 + 6 + 5 + 8 + 127 + 7 + 489 + 7 + 9 + 2 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 31540158817 + ... + 31540160927.

It is an arithmetic number, because the mean of its divisors is an integer number (284398994880).

Almost surely, 2^{66581277489792} is an apocalyptic number.

66581277489792 is a gapful number since it is divisible by the number (62) 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 66581277489792, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (109209214033920).

66581277489792 is an abundant number, since it is smaller than the sum of its proper divisors (151837150578048).

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

66581277489792 is a wasteful number, since it uses less digits than its factorization.

66581277489792 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3873 (or 3858 counting only the distinct ones).

The product of its digits is 5120962560, while the sum is 81.

The spelling of 66581277489792 in words is "sixty-six trillion, five hundred eighty-one billion, two hundred seventy-seven million, four hundred eighty-nine thousand, seven hundred ninety-two".