9961420581 has 20 divisors (see below), whose sum is σ = 17006447392. Its totient is φ = 5692240008.

The previous prime is 9961420577. The next prime is 9961420591. The reversal of 9961420581 is 1850241699.

9961420581 is a `hidden beast` number, since 9 + 9 + 61 + 4 + 2 + 0 + 581 = 666.

It is not a de Polignac number, because 9961420581 - 2² = 9961420577 is a prime.

It is a super-2 number, since 2×9961420581² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9961420531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 8783755 + ... + 8784888.

Almost surely, 2^9961420581 is an apocalyptic number.

It is an amenable number.

9961420581 is a deficient number, since it is larger than the sum of its proper divisors (7045026811).

9961420581 is a wasteful number, since it uses less digits than its factorization.

9961420581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17568662 (or 17568653 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 45.

The square root of 9961420581 is about 99806.9164988078. The cubic root of 9961420581 is about 2151.6605582005.

The spelling of 9961420581 in words is "nine billion, nine hundred sixty-one million, four hundred twenty thousand, five hundred eighty-one".