19991497 has 8 divisors (see below), whose sum is σ = 21076992. Its totient is φ = 18933600.

The previous prime is 19991483. The next prime is 19991509. The reversal of 19991497 is 79419991.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 19991497 - 2²³ = 11602889 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 19991497.

It is not an unprimeable number, because it can be changed into a prime (19991467) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5404 + ... + 8317.

It is an arithmetic number, because the mean of its divisors is an integer number (2634624).

Almost surely, 2^19991497 is an apocalyptic number.

It is an amenable number.

19991497 is a deficient number, since it is larger than the sum of its proper divisors (1085495).

19991497 is a wasteful number, since it uses less digits than its factorization.

19991497 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13799.

The product of its digits is 183708, while the sum is 49.

The square root of 19991497 is about 4471.1851896337. The cubic root of 19991497 is about 271.4032883850.

The spelling of 19991497 in words is "nineteen million, nine hundred ninety-one thousand, four hundred ninety-seven".