978642 has 40 divisors (see below), whose sum is σ = 2509056. Its totient is φ = 279288.

The previous prime is 978619. The next prime is 978643. The reversal of 978642 is 246879.

978642 is a `hidden beast` number, since 9 + 7 + 8 + 642 = 666.

It is a d-powerful number, because it can be written as 9⁶ + 7⁴ + 6⁷ + 8⁵ + 4⁵ + 2¹⁷ .

It is a nialpdrome in base 16.

It is a junction number, because it is equal to n+sod(n) for n = 978597 and 978606.

It is not an unprimeable number, because it can be changed into a prime (978643) 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 19 ways as a sum of consecutive naturals, for example, 703 + ... + 1565.

2⁹⁷⁸⁶⁴² is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 978642, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1254528).

978642 is an abundant number, since it is smaller than the sum of its proper divisors (1530414).

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

978642 is a wasteful number, since it uses less digits than its factorization.

978642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 884 (or 875 counting only the distinct ones).

The product of its digits is 24192, while the sum is 36.

The square root of 978642 is about 989.2633623055. The cubic root of 978642 is about 99.2829371655.

The spelling of 978642 in words is "nine hundred seventy-eight thousand, six hundred forty-two".