9978631 has 4 divisors (see below), whose sum is σ = 10746232. Its totient is φ = 9211032.

The previous prime is 9978613. The next prime is 9978637. The reversal of 9978631 is 1368799.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1368799 = 23 ⋅59513.

It is a cyclic number.

It is not a de Polignac number, because 9978631 - 2⁵ = 9978599 is a prime.

It is a super-2 number, since 2×9978631² = 199146153268322, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9978637) 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, 383781 + ... + 383806.

It is an arithmetic number, because the mean of its divisors is an integer number (2686558).

Almost surely, 2^9978631 is an apocalyptic number.

9978631 is a deficient number, since it is larger than the sum of its proper divisors (767601).

9978631 is a wasteful number, since it uses less digits than its factorization.

9978631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 767600.

The product of its digits is 81648, while the sum is 43.

The square root of 9978631 is about 3158.8971176662. The cubic root of 9978631 is about 215.2898991804.

It can be divided in two parts, 9978 and 631, that added together give a square (10609 = 103²).

The spelling of 9978631 in words is "nine million, nine hundred seventy-eight thousand, six hundred thirty-one".