66657406 has 4 divisors (see below), whose sum is σ = 99986112. Its totient is φ = 33328702.

The previous prime is 66657401. The next prime is 66657443. The reversal of 66657406 is 60475666.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66657401) 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 as a sum of consecutive naturals, namely, 16664350 + ... + 16664353.

It is an arithmetic number, because the mean of its divisors is an integer number (24996528).

Almost surely, 2^66657406 is an apocalyptic number.

66657406 is a deficient number, since it is larger than the sum of its proper divisors (33328706).

66657406 is a wasteful number, since it uses less digits than its factorization.

66657406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33328705.

The product of its (nonzero) digits is 181440, while the sum is 40.

The square root of 66657406 is about 8164.3986918817. The cubic root of 66657406 is about 405.4613570871.

The spelling of 66657406 in words is "sixty-six million, six hundred fifty-seven thousand, four hundred six".