9978491 has 4 divisors (see below), whose sum is σ = 10015584. Its totient is φ = 9941400.

The previous prime is 9978461. The next prime is 9978547. The reversal of 9978491 is 1948799.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 9978491 - 2⁶ = 9978427 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (9978431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18140 + ... + 18681.

It is an arithmetic number, because the mean of its divisors is an integer number (2503896).

Almost surely, 2^9978491 is an apocalyptic number.

9978491 is a deficient number, since it is larger than the sum of its proper divisors (37093).

9978491 is a wasteful number, since it uses less digits than its factorization.

9978491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37092.

The product of its digits is 163296, while the sum is 47.

The square root of 9978491 is about 3158.8749579558. The cubic root of 9978491 is about 215.2888923380.

The spelling of 9978491 in words is "nine million, nine hundred seventy-eight thousand, four hundred ninety-one".