978531840 has 720 divisors, whose sum is σ = 4160139984. Its totient is φ = 218972160.

The previous prime is 978531821. The next prime is 978531847. The reversal of 978531840 is 48135879.

978531840 is a `hidden beast` number, since 9 + 78 + 531 + 8 + 40 = 666.

It is a tau number, because it is divible by the number of its divisors (720).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (978531847) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 75271674 + ... + 75271686.

Almost surely, 2^978531840 is an apocalyptic number.

978531840 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 978531840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2080069992).

978531840 is an abundant number, since it is smaller than the sum of its proper divisors (3181608144).

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

978531840 is a wasteful number, since it uses less digits than its factorization.

978531840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73 (or 34 counting only the distinct ones).

The product of its (nonzero) digits is 241920, while the sum is 45.

The square root of 978531840 is about 31281.4935704803. The cubic root of 978531840 is about 992.7921179278.

The spelling of 978531840 in words is "nine hundred seventy-eight million, five hundred thirty-one thousand, eight hundred forty".