66400023 has 4 divisors (see below), whose sum is σ = 88533368. Its totient is φ = 44266680.

The previous prime is 66400021. The next prime is 66400051. The reversal of 66400023 is 32000466.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 66400023 - 2¹ = 66400021 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66400021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11066668 + ... + 11066673.

It is an arithmetic number, because the mean of its divisors is an integer number (22133342).

Almost surely, 2^66400023 is an apocalyptic number.

66400023 is a deficient number, since it is larger than the sum of its proper divisors (22133345).

66400023 is a wasteful number, since it uses less digits than its factorization.

66400023 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22133344.

The product of its (nonzero) digits is 864, while the sum is 21.

The square root of 66400023 is about 8148.6209262672. The cubic root of 66400023 is about 404.9388171561.

Adding to 66400023 its reverse (32000466), we get a palindrome (98400489).

The spelling of 66400023 in words is "sixty-six million, four hundred thousand, twenty-three".