19639693 has 2 divisors, whose sum is σ = 19639694. Its totient is φ = 19639692.

The previous prime is 19639681. The next prime is 19639703. The reversal of 19639693 is 39693691.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17825284 + 1814409 = 4222^2 + 1347^2 .

It is a cyclic number.

It is not a de Polignac number, because 19639693 - 2⁹ = 19639181 is a prime.

It is a super-2 number, since 2×19639693² = 771435082268498, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19639663) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9819846 + 9819847.

It is an arithmetic number, because the mean of its divisors is an integer number (9819847).

Almost surely, 2^19639693 is an apocalyptic number.

It is an amenable number.

19639693 is a deficient number, since it is larger than the sum of its proper divisors (1).

19639693 is an equidigital number, since it uses as much as digits as its factorization.

19639693 is an evil number, because the sum of its binary digits is even.

The product of its digits is 236196, while the sum is 46.

The square root of 19639693 is about 4431.6693243066. The cubic root of 19639693 is about 269.8018344738.

The spelling of 19639693 in words is "nineteen million, six hundred thirty-nine thousand, six hundred ninety-three".