19997615 has 16 divisors (see below), whose sum is σ = 26265600. Its totient is φ = 14495520.

The previous prime is 19997609. The next prime is 19997641. The reversal of 19997615 is 51679991.

It is not a de Polignac number, because 19997615 - 2⁴ = 19997599 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 19997615.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 32642 + ... + 33248.

It is an arithmetic number, because the mean of its divisors is an integer number (1641600).

Almost surely, 2^19997615 is an apocalyptic number.

19997615 is a deficient number, since it is larger than the sum of its proper divisors (6267985).

19997615 is a wasteful number, since it uses less digits than its factorization.

19997615 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1222.

The product of its digits is 153090, while the sum is 47.

The square root of 19997615 is about 4471.8692959433. The cubic root of 19997615 is about 271.4309714205.

It can be divided in two parts, 199976 and 15, that added together give a palindrome (199991).

The spelling of 19997615 in words is "nineteen million, nine hundred ninety-seven thousand, six hundred fifteen".