19990597 has 4 divisors (see below), whose sum is σ = 21807936. Its totient is φ = 18173260.

The previous prime is 19990591. The next prime is 19990601. The reversal of 19990597 is 79509991.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19990597 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 19990597.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19990591) 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, 908653 + ... + 908674.

It is an arithmetic number, because the mean of its divisors is an integer number (5451984).

Almost surely, 2^19990597 is an apocalyptic number.

It is an amenable number.

19990597 is a deficient number, since it is larger than the sum of its proper divisors (1817339).

19990597 is a wasteful number, since it uses less digits than its factorization.

19990597 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1817338.

The product of its (nonzero) digits is 229635, while the sum is 49.

The square root of 19990597 is about 4471.0845440452. The cubic root of 19990597 is about 271.3992155430.

It can be divided in two parts, 199905 and 97, that added together give a palindrome (200002).

The spelling of 19990597 in words is "nineteen million, nine hundred ninety thousand, five hundred ninety-seven".