19899071 has 4 divisors (see below), whose sum is σ = 20764272. Its totient is φ = 19033872.

The previous prime is 19899049. The next prime is 19899079. The reversal of 19899071 is 17099891.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19899071 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19899079) 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, 432566 + ... + 432611.

It is an arithmetic number, because the mean of its divisors is an integer number (5191068).

Almost surely, 2^19899071 is an apocalyptic number.

19899071 is a deficient number, since it is larger than the sum of its proper divisors (865201).

19899071 is an equidigital number, since it uses as much as digits as its factorization.

19899071 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 865200.

The product of its (nonzero) digits is 40824, while the sum is 44.

The square root of 19899071 is about 4460.8374774251. The cubic root of 19899071 is about 270.9843856601.

The spelling of 19899071 in words is "nineteen million, eight hundred ninety-nine thousand, seventy-one".