19993261 has 2 divisors, whose sum is σ = 19993262. Its totient is φ = 19993260.

The previous prime is 19993249. The next prime is 19993273. The reversal of 19993261 is 16239991.

It is a balanced prime because it is at equal distance from previous prime (19993249) and next prime (19993273).

It can be written as a sum of positive squares in only one way, i.e., 18224361 + 1768900 = 4269^2 + 1330^2 .

It is an emirp because it is prime and its reverse (16239991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19993261 - 2¹⁷ = 19862189 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19993201) 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, 9996630 + 9996631.

It is an arithmetic number, because the mean of its divisors is an integer number (9996631).

Almost surely, 2^19993261 is an apocalyptic number.

It is an amenable number.

19993261 is a deficient number, since it is larger than the sum of its proper divisors (1).

19993261 is an equidigital number, since it uses as much as digits as its factorization.

19993261 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 26244, while the sum is 40.

The square root of 19993261 is about 4471.3824484157. The cubic root of 19993261 is about 271.4112708007.

The spelling of 19993261 in words is "nineteen million, nine hundred ninety-three thousand, two hundred sixty-one".