66667280 has 40 divisors (see below), whose sum is σ = 155929752. Its totient is φ = 26507264.

The previous prime is 66667277. The next prime is 66667283. The reversal of 66667280 is 8276666.

It is an interprime number because it is at equal distance from previous prime (66667277) and next prime (66667283).

It can be written as a sum of positive squares in 4 ways, for example, as 6697744 + 59969536 = 2588^2 + 7744^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is not an unprimeable number, because it can be changed into a prime (66667283) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11432 + ... + 16248.

Almost surely, 2^66667280 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66667280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (77964876).

66667280 is an abundant number, since it is smaller than the sum of its proper divisors (89262472).

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

66667280 is a wasteful number, since it uses less digits than its factorization.

66667280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5003 (or 4997 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 41.

The square root of 66667280 is about 8165.0033680336. The cubic root of 66667280 is about 405.4813765068.

The spelling of 66667280 in words is "sixty-six million, six hundred sixty-seven thousand, two hundred eighty".