991619249 has 2 divisors, whose sum is σ = 991619250. Its totient is φ = 991619248.

The previous prime is 991619149. The next prime is 991619261. The reversal of 991619249 is 942916199.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 990990400 + 628849 = 31480^2 + 793^2 .

It is a cyclic number.

It is not a de Polignac number, because 991619249 - 2²⁸ = 723183793 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 991619197 and 991619206.

It is not a weakly prime, because it can be changed into another prime (991619149) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495809624 + 495809625.

It is an arithmetic number, because the mean of its divisors is an integer number (495809625).

Almost surely, 2^991619249 is an apocalyptic number.

It is an amenable number.

991619249 is a deficient number, since it is larger than the sum of its proper divisors (1).

991619249 is an equidigital number, since it uses as much as digits as its factorization.

991619249 is an evil number, because the sum of its binary digits is even.

The product of its digits is 314928, while the sum is 50.

The square root of 991619249 is about 31489.9864877710. The cubic root of 991619249 is about 997.1985756836.

The spelling of 991619249 in words is "nine hundred ninety-one million, six hundred nineteen thousand, two hundred forty-nine".