991644441 has 4 divisors (see below), whose sum is σ = 1322192592. Its totient is φ = 661096292.

The previous prime is 991644403. The next prime is 991644449. The reversal of 991644441 is 144446199.

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 991644441 - 2⁶ = 991644377 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 991644393 and 991644402.

It is not an unprimeable number, because it can be changed into a prime (991644449) 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, 165274071 + ... + 165274076.

It is an arithmetic number, because the mean of its divisors is an integer number (330548148).

Almost surely, 2^991644441 is an apocalyptic number.

It is an amenable number.

991644441 is a deficient number, since it is larger than the sum of its proper divisors (330548151).

991644441 is a wasteful number, since it uses less digits than its factorization.

991644441 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 330548150.

The product of its digits is 124416, while the sum is 42.

The square root of 991644441 is about 31490.3864854022. The cubic root of 991644441 is about 997.2070201929.

The spelling of 991644441 in words is "nine hundred ninety-one million, six hundred forty-four thousand, four hundred forty-one".