9978401520 has 240 divisors, whose sum is σ = 35035852800. Its totient is φ = 2542026240.

The previous prime is 9978401497. The next prime is 9978401539. The reversal of 9978401520 is 251048799.

It is a tau number, because it is divible by the number of its divisors (240).

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1760451 + ... + 1766109.

It is an arithmetic number, because the mean of its divisors is an integer number (145982720).

Almost surely, 2^9978401520 is an apocalyptic number.

9978401520 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 9978401520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (17517926400).

9978401520 is an abundant number, since it is smaller than the sum of its proper divisors (25057451280).

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

9978401520 is a wasteful number, since it uses less digits than its factorization.

9978401520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5788 (or 5779 counting only the distinct ones).

The product of its (nonzero) digits is 181440, while the sum is 45.

The square root of 9978401520 is about 99891.9492251503. The cubic root of 9978401520 is about 2152.8824881694.

The spelling of 9978401520 in words is "nine billion, nine hundred seventy-eight million, four hundred one thousand, five hundred twenty".