66550491 has 20 divisors (see below), whose sum is σ = 113618032. Its totient is φ = 38028528.

The previous prime is 66550487. The next prime is 66550499. The reversal of 66550491 is 19405566.

66550491 is a `hidden beast` number, since 6 + 65 + 504 + 91 = 666.

It is not a de Polignac number, because 66550491 - 2² = 66550487 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66550499) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 58120 + ... + 59253.

Almost surely, 2^66550491 is an apocalyptic number.

66550491 is a deficient number, since it is larger than the sum of its proper divisors (47067541).

66550491 is a wasteful number, since it uses less digits than its factorization.

66550491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 117392 (or 117383 counting only the distinct ones).

The product of its (nonzero) digits is 32400, while the sum is 36.

The square root of 66550491 is about 8157.8484295799. The cubic root of 66550491 is about 405.2444614648.

The spelling of 66550491 in words is "sixty-six million, five hundred fifty thousand, four hundred ninety-one".