19999505 has 4 divisors (see below), whose sum is σ = 23999412. Its totient is φ = 15999600.

The previous prime is 19999501. The next prime is 19999519. The reversal of 19999505 is 50599991.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 6390784 + 13608721 = 2528^2 + 3689^2 .

It is not a de Polignac number, because 19999505 - 2² = 19999501 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 19999505.

It is not an unprimeable number, because it can be changed into a prime (19999501) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1999946 + ... + 1999955.

It is an arithmetic number, because the mean of its divisors is an integer number (5999853).

Almost surely, 2^19999505 is an apocalyptic number.

It is an amenable number.

19999505 is a deficient number, since it is larger than the sum of its proper divisors (3999907).

19999505 is an equidigital number, since it uses as much as digits as its factorization.

19999505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3999906.

The product of its (nonzero) digits is 164025, while the sum is 47.

The square root of 19999505 is about 4472.0806119747. The cubic root of 19999505 is about 271.4395222465.

The spelling of 19999505 in words is "nineteen million, nine hundred ninety-nine thousand, five hundred five".