209423887 has 2 divisors, whose sum is σ = 209423888. Its totient is φ = 209423886.

The previous prime is 209423783. The next prime is 209423899. The reversal of 209423887 is 788324902.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 209423887 - 2¹⁹ = 208899599 is a prime.

It is a super-4 number, since 4×209423887⁴ (a number of 34 digits) contains 4444 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (209423387) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104711943 + 104711944.

It is an arithmetic number, because the mean of its divisors is an integer number (104711944).

Almost surely, 2^209423887 is an apocalyptic number.

209423887 is a deficient number, since it is larger than the sum of its proper divisors (1).

209423887 is an equidigital number, since it uses as much as digits as its factorization.

209423887 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 193536, while the sum is 43.

The square root of 209423887 is about 14471.4853073207. The cubic root of 209423887 is about 593.8481465530.

The spelling of 209423887 in words is "two hundred nine million, four hundred twenty-three thousand, eight hundred eighty-seven".