19990811 has 2 divisors, whose sum is σ = 19990812. Its totient is φ = 19990810.

The previous prime is 19990801. The next prime is 19990849. The reversal of 19990811 is 11809991.

It is a happy number.

It is an a-pointer prime, because the next prime (19990849) can be obtained adding 19990811 to its sum of digits (38).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 19990811 - 2²² = 15796507 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (19990801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9995405 + 9995406.

It is an arithmetic number, because the mean of its divisors is an integer number (9995406).

Almost surely, 2^19990811 is an apocalyptic number.

19990811 is a deficient number, since it is larger than the sum of its proper divisors (1).

19990811 is an equidigital number, since it uses as much as digits as its factorization.

19990811 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5832, while the sum is 38.

The square root of 19990811 is about 4471.1084755349. The cubic root of 19990811 is about 271.4001839854.

The spelling of 19990811 in words is "nineteen million, nine hundred ninety thousand, eight hundred eleven".