9961645380 has 96 divisors (see below), whose sum is σ = 29749337856. Its totient is φ = 2481893376.

The previous prime is 9961645349. The next prime is 9961645381. The reversal of 9961645380 is 835461699.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is not an unprimeable number, because it can be changed into a prime (9961645381) 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 31 ways as a sum of consecutive naturals, for example, 104097 + ... + 175383.

It is an arithmetic number, because the mean of its divisors is an integer number (309888936).

Almost surely, 2^9961645380 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 9961645380, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (14874668928).

9961645380 is an abundant number, since it is smaller than the sum of its proper divisors (19787692476).

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

9961645380 is a wasteful number, since it uses less digits than its factorization.

9961645380 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71453 (or 71451 counting only the distinct ones).

The product of its (nonzero) digits is 1399680, while the sum is 51.

The square root of 9961645380 is about 99808.0426619018. The cubic root of 9961645380 is about 2151.6767435595.

The spelling of 9961645380 in words is "nine billion, nine hundred sixty-one million, six hundred forty-five thousand, three hundred eighty".