213891217409 has 8 divisors (see below), whose sum is σ = 223547880360. Its totient is φ = 204386628096.

The previous prime is 213891217403. The next prime is 213891217451. The reversal of 213891217409 is 904712198312.

It can be written as a sum of positive squares in 4 ways, for example, as 72630250000 + 141260967409 = 269500^2 + 375847^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-213891217409 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (213891217403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 38015534 + ... + 38021159.

It is an arithmetic number, because the mean of its divisors is an integer number (27943485045).

Almost surely, 2^213891217409 is an apocalyptic number.

213891217409 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

213891217409 is a deficient number, since it is larger than the sum of its proper divisors (9656662951).

213891217409 is an equidigital number, since it uses as much as digits as its factorization.

213891217409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76036819.

The product of its (nonzero) digits is 217728, while the sum is 47.

The spelling of 213891217409 in words is "two hundred thirteen billion, eight hundred ninety-one million, two hundred seventeen thousand, four hundred nine".