9991061 has 4 divisors (see below), whose sum is σ = 10038624. Its totient is φ = 9943500.

The previous prime is 9991057. The next prime is 9991063. The reversal of 9991061 is 1601999.

9991061 is digitally balanced in base 2 and base 3, because in such bases it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 9991061 - 2² = 9991057 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9991063) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 23465 + ... + 23886.

It is an arithmetic number, because the mean of its divisors is an integer number (2509656).

Almost surely, 2^9991061 is an apocalyptic number.

It is an amenable number.

9991061 is a deficient number, since it is larger than the sum of its proper divisors (47563).

9991061 is a wasteful number, since it uses less digits than its factorization.

9991061 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47562.

The product of its (nonzero) digits is 4374, while the sum is 35.

The square root of 9991061 is about 3160.8639641718. The cubic root of 9991061 is about 215.3792548934.

The spelling of 9991061 in words is "nine million, nine hundred ninety-one thousand, sixty-one".