19930891 has 2 divisors, whose sum is σ = 19930892. Its totient is φ = 19930890.

The previous prime is 19930877. The next prime is 19930921. The reversal of 19930891 is 19803991.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 19930891 - 2¹³ = 19922699 is a prime.

It is not a weakly prime, because it can be changed into another prime (19930871) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9965445 + 9965446.

It is an arithmetic number, because the mean of its divisors is an integer number (9965446).

Almost surely, 2^19930891 is an apocalyptic number.

19930891 is a deficient number, since it is larger than the sum of its proper divisors (1).

19930891 is an equidigital number, since it uses as much as digits as its factorization.

19930891 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 17496, while the sum is 40.

The square root of 19930891 is about 4464.4026476114. The cubic root of 19930891 is about 271.1287497047.

The spelling of 19930891 in words is "nineteen million, nine hundred thirty thousand, eight hundred ninety-one".