6663491 has 4 divisors (see below), whose sum is σ = 6953232. Its totient is φ = 6373752.

The previous prime is 6663487. The next prime is 6663493. The reversal of 6663491 is 1943666.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1943666 = 2 ⋅971833.

It is a cyclic number.

It is not a de Polignac number, because 6663491 - 2² = 6663487 is a prime.

It is a super-2 number, since 2×6663491² = 88804224614162, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6663493) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 144836 + ... + 144881.

It is an arithmetic number, because the mean of its divisors is an integer number (1738308).

Almost surely, 2^6663491 is an apocalyptic number.

6663491 is a deficient number, since it is larger than the sum of its proper divisors (289741).

6663491 is a wasteful number, since it uses less digits than its factorization.

6663491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 289740.

The product of its digits is 23328, while the sum is 35.

The square root of 6663491 is about 2581.3738590138. The cubic root of 6663491 is about 188.1773168624.

The spelling of 6663491 in words is "six million, six hundred sixty-three thousand, four hundred ninety-one".