654668991 has 12 divisors (see below), whose sum is σ = 947996400. Its totient is φ = 435355200.

The previous prime is 654668983. The next prime is 654668999. The reversal of 654668991 is 199866456.

It is a happy number.

654668991 is a `hidden beast` number, since 6 + 546 + 6 + 8 + 9 + 91 = 666.

It is an interprime number because it is at equal distance from previous prime (654668983) and next prime (654668999).

It is not a de Polignac number, because 654668991 - 2³ = 654668983 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (654668999) 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 11 ways as a sum of consecutive naturals, for example, 87091 + ... + 94308.

It is an arithmetic number, because the mean of its divisors is an integer number (78999700).

Almost surely, 2^654668991 is an apocalyptic number.

654668991 is a deficient number, since it is larger than the sum of its proper divisors (293327409).

654668991 is a wasteful number, since it uses less digits than its factorization.

654668991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 181806 (or 181803 counting only the distinct ones).

The product of its digits is 2799360, while the sum is 54.

The square root of 654668991 is about 25586.5001709886. The cubic root of 654668991 is about 868.3082423513.

The spelling of 654668991 in words is "six hundred fifty-four million, six hundred sixty-eight thousand, nine hundred ninety-one".