66400667 has 8 divisors (see below), whose sum is σ = 68643840. Its totient is φ = 64163880.

The previous prime is 66400661. The next prime is 66400751. The reversal of 66400667 is 76600466.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 66400667 - 2²⁴ = 49623451 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66400661) 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, 29384 + ... + 31562.

It is an arithmetic number, because the mean of its divisors is an integer number (8580480).

Almost surely, 2^66400667 is an apocalyptic number.

66400667 is a deficient number, since it is larger than the sum of its proper divisors (2243173).

66400667 is a wasteful number, since it uses less digits than its factorization.

66400667 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3193.

The product of its (nonzero) digits is 36288, while the sum is 35.

The square root of 66400667 is about 8148.6604420604. The cubic root of 66400667 is about 404.9401262909.

The spelling of 66400667 in words is "sixty-six million, four hundred thousand, six hundred sixty-seven".