991041421 has 4 divisors (see below), whose sum is σ = 1005833152. Its totient is φ = 976249692.

The previous prime is 991041419. The next prime is 991041481. The reversal of 991041421 is 124140199.

991041421 is digitally balanced in base 2, because in such base 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 991041421 - 2¹ = 991041419 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 (991041481) 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, 7395765 + ... + 7395898.

It is an arithmetic number, because the mean of its divisors is an integer number (251458288).

Almost surely, 2^991041421 is an apocalyptic number.

It is an amenable number.

991041421 is a deficient number, since it is larger than the sum of its proper divisors (14791731).

991041421 is a wasteful number, since it uses less digits than its factorization.

991041421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14791730.

The product of its (nonzero) digits is 2592, while the sum is 31.

The square root of 991041421 is about 31480.8103612343. The cubic root of 991041421 is about 997.0048450030.

The spelling of 991041421 in words is "nine hundred ninety-one million, forty-one thousand, four hundred twenty-one".