491898978 has 24 divisors (see below), whose sum is σ = 1128474828. Its totient is φ = 154321152.

The previous prime is 491898971. The next prime is 491899003. The reversal of 491898978 is 879898194.

It can be written as a sum of positive squares in 2 ways, for example, as 491641929 + 257049 = 22173^2 + 507^2 .

It is not an unprimeable number, because it can be changed into a prime (491898971) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 803451 + ... + 804062.

Almost surely, 2^491898978 is an apocalyptic number.

491898978 is an abundant number, since it is smaller than the sum of its proper divisors (636575850).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

491898978 is a wasteful number, since it uses less digits than its factorization.

491898978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1607538 (or 1607535 counting only the distinct ones).

The product of its digits is 10450944, while the sum is 63.

The square root of 491898978 is about 22178.7956841664. The cubic root of 491898978 is about 789.3906415656.

The spelling of 491898978 in words is "four hundred ninety-one million, eight hundred ninety-eight thousand, nine hundred seventy-eight".