66750409 has 16 divisors (see below), whose sum is σ = 76423680. Its totient is φ = 57744000.

The previous prime is 66750403. The next prime is 66750413. The reversal of 66750409 is 90405766.

It is a cyclic number.

It is not a de Polignac number, because 66750409 - 2⁹ = 66749897 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66750403) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19197 + ... + 22405.

It is an arithmetic number, because the mean of its divisors is an integer number (4776480).

Almost surely, 2^66750409 is an apocalyptic number.

It is an amenable number.

66750409 is a deficient number, since it is larger than the sum of its proper divisors (9673271).

66750409 is a wasteful number, since it uses less digits than its factorization.

66750409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3312.

The product of its (nonzero) digits is 45360, while the sum is 37.

The square root of 66750409 is about 8170.0923495393. The cubic root of 66750409 is about 405.6498412615.

It can be divided in two parts, 667 and 50409, that added together give a square (51076 = 226²).

The spelling of 66750409 in words is "sixty-six million, seven hundred fifty thousand, four hundred nine".