66531638 has 16 divisors (see below), whose sum is σ = 101954160. Its totient is φ = 32554656.

The previous prime is 66531623. The next prime is 66531653. The reversal of 66531638 is 83613566.

It is an interprime number because it is at equal distance from previous prime (66531623) and next prime (66531653).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16256 + ... + 19932.

It is an arithmetic number, because the mean of its divisors is an integer number (6372135).

Almost surely, 2^66531638 is an apocalyptic number.

66531638 is a deficient number, since it is larger than the sum of its proper divisors (35422522).

66531638 is a wasteful number, since it uses less digits than its factorization.

66531638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3871.

The product of its digits is 77760, while the sum is 38.

The square root of 66531638 is about 8156.6928347217. The cubic root of 66531638 is about 405.2061907960.

The spelling of 66531638 in words is "sixty-six million, five hundred thirty-one thousand, six hundred thirty-eight".