213664705 has 8 divisors (see below), whose sum is σ = 256892904. Its totient is φ = 170601600.

The previous prime is 213664697. The next prime is 213664739. The reversal of 213664705 is 507466312.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 58736896 + 154927809 = 7664^2 + 12447^2 .

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

It is not a de Polignac number, because 213664705 - 2³ = 213664697 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 38406 + ... + 43615.

It is an arithmetic number, because the mean of its divisors is an integer number (32111613).

Almost surely, 2^213664705 is an apocalyptic number.

It is an amenable number.

213664705 is a deficient number, since it is larger than the sum of its proper divisors (43228199).

213664705 is an equidigital number, since it uses as much as digits as its factorization.

213664705 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82547.

The product of its (nonzero) digits is 30240, while the sum is 34.

The square root of 213664705 is about 14617.2741987007. The cubic root of 213664705 is about 597.8298500267.

It can be divided in two parts, 213664 and 705, that added together give a square (214369 = 463²).

The spelling of 213664705 in words is "two hundred thirteen million, six hundred sixty-four thousand, seven hundred five".