66257280 has 96 divisors (see below), whose sum is σ = 228814560. Its totient is φ = 17667072.

The previous prime is 66257251. The next prime is 66257293. The reversal of 66257280 is 8275266.

66257280 is a `hidden beast` number, since 6 + 6 + 2 + 572 + 80 = 666.

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a zygodrome in base 2.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9 + ... + 11511.

It is an arithmetic number, because the mean of its divisors is an integer number (2383485).

Almost surely, 2^66257280 is an apocalyptic number.

66257280 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 66257280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (114407280).

66257280 is an abundant number, since it is smaller than the sum of its proper divisors (162557280).

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

66257280 is a wasteful number, since it uses less digits than its factorization.

66257280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11528 (or 11513 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 36.

The square root of 66257280 is about 8139.8574926101. The cubic root of 66257280 is about 404.6484374822.

Adding to 66257280 its sum of digits (36), we get a triangular number (66257316 = T₁₁₅₁₁).

The spelling of 66257280 in words is "sixty-six million, two hundred fifty-seven thousand, two hundred eighty".