208721893 has 4 divisors (see below), whose sum is σ = 209320300. Its totient is φ = 208123488.

The previous prime is 208721873. The next prime is 208721911. The reversal of 208721893 is 398127802.

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

It can be written as a sum of positive squares in 2 ways, for example, as 152201569 + 56520324 = 12337^2 + 7518^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-208721893 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 (208721813) 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, 298680 + ... + 299377.

It is an arithmetic number, because the mean of its divisors is an integer number (52330075).

Almost surely, 2^208721893 is an apocalyptic number.

It is an amenable number.

208721893 is a deficient number, since it is larger than the sum of its proper divisors (598407).

208721893 is an equidigital number, since it uses as much as digits as its factorization.

208721893 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 598406.

The product of its (nonzero) digits is 48384, while the sum is 40.

The square root of 208721893 is about 14447.2105612122. The cubic root of 208721893 is about 593.1838725996.

The spelling of 208721893 in words is "two hundred eight million, seven hundred twenty-one thousand, eight hundred ninety-three".