213721305 has 32 divisors (see below), whose sum is σ = 397440000. Its totient is φ = 96042432.

The previous prime is 213721283. The next prime is 213721327. The reversal of 213721305 is 503127312.

213721305 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (213721283) and next prime (213721327).

It is not a de Polignac number, because 213721305 - 2⁶ = 213721241 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 11055 + ... + 23444.

It is an arithmetic number, because the mean of its divisors is an integer number (12420000).

Almost surely, 2^213721305 is an apocalyptic number.

It is an amenable number.

213721305 is a deficient number, since it is larger than the sum of its proper divisors (183718695).

213721305 is a wasteful number, since it uses less digits than its factorization.

213721305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34573.

The product of its (nonzero) digits is 1260, while the sum is 24.

The square root of 213721305 is about 14619.2101359820. The cubic root of 213721305 is about 597.8826339467.

Adding to 213721305 its reverse (503127312), we get a palindrome (716848617).

The spelling of 213721305 in words is "two hundred thirteen million, seven hundred twenty-one thousand, three hundred five".