19919623 has 2 divisors, whose sum is σ = 19919624. Its totient is φ = 19919622.

The previous prime is 19919617. The next prime is 19919651. The reversal of 19919623 is 32691991.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 19919623 - 2⁵ = 19919591 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19919693) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9959811 + 9959812.

It is an arithmetic number, because the mean of its divisors is an integer number (9959812).

Almost surely, 2^19919623 is an apocalyptic number.

19919623 is a deficient number, since it is larger than the sum of its proper divisors (1).

19919623 is an equidigital number, since it uses as much as digits as its factorization.

19919623 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 19919623 is about 4463.1404862496. The cubic root of 19919623 is about 271.0776455390.

The spelling of 19919623 in words is "nineteen million, nine hundred nineteen thousand, six hundred twenty-three".