19919921237 has 2 divisors, whose sum is σ = 19919921238. Its totient is φ = 19919921236.

The previous prime is 19919921201. The next prime is 19919921249. The reversal of 19919921237 is 73212991991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17367549796 + 2552371441 = 131786^2 + 50521^2 .

It is an emirp because it is prime and its reverse (73212991991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19919921237 - 2⁸ = 19919920981 is a prime.

It is a super-2 number, since 2×19919921237² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19919921267) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9959960618 + 9959960619.

It is an arithmetic number, because the mean of its divisors is an integer number (9959960619).

Almost surely, 2^19919921237 is an apocalyptic number.

It is an amenable number.

19919921237 is a deficient number, since it is larger than the sum of its proper divisors (1).

19919921237 is an equidigital number, since it uses as much as digits as its factorization.

19919921237 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 551124, while the sum is 53.

The spelling of 19919921237 in words is "nineteen billion, nine hundred nineteen million, nine hundred twenty-one thousand, two hundred thirty-seven".