66388730 has 16 divisors (see below), whose sum is σ = 122730120. Its totient is φ = 25837632.

The previous prime is 66388727. The next prime is 66388733. The reversal of 66388730 is 3788366.

It is an interprime number because it is at equal distance from previous prime (66388727) and next prime (66388733).

It can be written as a sum of positive squares in 4 ways, for example, as 63952009 + 2436721 = 7997^2 + 1561^2 .

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (66388733) 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, 89345 + ... + 90084.

Almost surely, 2^66388730 is an apocalyptic number.

66388730 is a deficient number, since it is larger than the sum of its proper divisors (56341390).

66388730 is a wasteful number, since it uses less digits than its factorization.

66388730 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 179473.

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

The square root of 66388730 is about 8147.9279574626. The cubic root of 66388730 is about 404.9158591653.

The spelling of 66388730 in words is "sixty-six million, three hundred eighty-eight thousand, seven hundred thirty".