20871499 has 4 divisors (see below), whose sum is σ = 22768920. Its totient is φ = 18974080.

The previous prime is 20871497. The next prime is 20871509. The reversal of 20871499 is 99417802.

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

It is a cyclic number.

It is not a de Polignac number, because 20871499 - 2¹ = 20871497 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20871491) 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, 948694 + ... + 948715.

It is an arithmetic number, because the mean of its divisors is an integer number (5692230).

Almost surely, 2^20871499 is an apocalyptic number.

20871499 is a deficient number, since it is larger than the sum of its proper divisors (1897421).

20871499 is a wasteful number, since it uses less digits than its factorization.

20871499 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1897420.

The product of its (nonzero) digits is 36288, while the sum is 40.

The square root of 20871499 is about 4568.5335721651. The cubic root of 20871499 is about 275.3285285794.

The spelling of 20871499 in words is "twenty million, eight hundred seventy-one thousand, four hundred ninety-nine".