991219049 has 4 divisors (see below), whose sum is σ = 1012308864. Its totient is φ = 970129236.

The previous prime is 991219027. The next prime is 991219121. The reversal of 991219049 is 940912199.

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, and also an emirpimes, since its reverse is a distinct semiprime: 940912199 = 79 ⋅11910281.

It is a cyclic number.

It is not a de Polignac number, because 991219049 - 2¹² = 991214953 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (991219349) 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, 10544837 + ... + 10544930.

It is an arithmetic number, because the mean of its divisors is an integer number (253077216).

Almost surely, 2^991219049 is an apocalyptic number.

It is an amenable number.

991219049 is a deficient number, since it is larger than the sum of its proper divisors (21089815).

991219049 is a wasteful number, since it uses less digits than its factorization.

991219049 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21089814.

The product of its (nonzero) digits is 52488, while the sum is 44.

The square root of 991219049 is about 31483.6314455623. The cubic root of 991219049 is about 997.0644070601.

The spelling of 991219049 in words is "nine hundred ninety-one million, two hundred nineteen thousand, forty-nine".