19915123 has 2 divisors, whose sum is σ = 19915124. Its totient is φ = 19915122.

The previous prime is 19915117. The next prime is 19915151. The reversal of 19915123 is 32151991.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19915123 is a prime.

It is a super-2 number, since 2×19915123² = 793224248210258, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (19915163) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9957561 + 9957562.

It is an arithmetic number, because the mean of its divisors is an integer number (9957562).

Almost surely, 2^19915123 is an apocalyptic number.

19915123 is a deficient number, since it is larger than the sum of its proper divisors (1).

19915123 is an equidigital number, since it uses as much as digits as its factorization.

19915123 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2430, while the sum is 31.

The square root of 19915123 is about 4462.6363284498. The cubic root of 19915123 is about 271.0572311420.

The spelling of 19915123 in words is "nineteen million, nine hundred fifteen thousand, one hundred twenty-three".