209256005 has 16 divisors (see below), whose sum is σ = 293981184. Its totient is φ = 139989120.

The previous prime is 209255993. The next prime is 209256007. The reversal of 209256005 is 500652902.

It is not a de Polignac number, because 209256005 - 2¹⁶ = 209190469 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (209256007) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 71477 + ... + 74346.

It is an arithmetic number, because the mean of its divisors is an integer number (18373824).

Almost surely, 2^209256005 is an apocalyptic number.

It is an amenable number.

209256005 is a deficient number, since it is larger than the sum of its proper divisors (84725179).

209256005 is a wasteful number, since it uses less digits than its factorization.

209256005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 145876.

The product of its (nonzero) digits is 5400, while the sum is 29.

The square root of 209256005 is about 14465.6837031645. The cubic root of 209256005 is about 593.6894205230.

The spelling of 209256005 in words is "two hundred nine million, two hundred fifty-six thousand, five".