19228991 has 4 divisors (see below), whose sum is σ = 19246584. Its totient is φ = 19211400.

The previous prime is 19228987. The next prime is 19229009. The reversal of 19228991 is 19982291.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 19228991 - 2² = 19228987 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 (19228981) 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, 7040 + ... + 9381.

It is an arithmetic number, because the mean of its divisors is an integer number (4811646).

Almost surely, 2^19228991 is an apocalyptic number.

19228991 is a deficient number, since it is larger than the sum of its proper divisors (17593).

19228991 is a wasteful number, since it uses less digits than its factorization.

19228991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17592.

The product of its digits is 23328, while the sum is 41.

The square root of 19228991 is about 4385.0873423456. The cubic root of 19228991 is about 267.9078867740.

The spelling of 19228991 in words is "nineteen million, two hundred twenty-eight thousand, nine hundred ninety-one".