9991562021 has 12 divisors (see below), whose sum is σ = 11625012288. Its totient is φ = 8562593592.

The previous prime is 9991562011. The next prime is 9991562081. The reversal of 9991562021 is 1202651999.

It is a de Polignac number, because none of the positive numbers 2^k-9991562021 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9991562011) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 299060 + ... + 330786.

It is an arithmetic number, because the mean of its divisors is an integer number (968751024).

Almost surely, 2^9991562021 is an apocalyptic number.

It is an amenable number.

9991562021 is a deficient number, since it is larger than the sum of its proper divisors (1633450267).

9991562021 is a wasteful number, since it uses less digits than its factorization.

9991562021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38168 (or 38161 counting only the distinct ones).

The product of its (nonzero) digits is 87480, while the sum is 44.

The square root of 9991562021 is about 99957.8012013069. The cubic root of 9991562021 is about 2153.8285503577.

The spelling of 9991562021 in words is "nine billion, nine hundred ninety-one million, five hundred sixty-two thousand, twenty-one".