213543721 has 4 divisors (see below), whose sum is σ = 214125952. Its totient is φ = 212961492.

The previous prime is 213543643. The next prime is 213543727. The reversal of 213543721 is 127345312.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 213543721 - 2¹¹ = 213541673 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 213543721.

It is not an unprimeable number, because it can be changed into a prime (213543727) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 290565 + ... + 291298.

It is an arithmetic number, because the mean of its divisors is an integer number (53531488).

Almost surely, 2^213543721 is an apocalyptic number.

It is an amenable number.

213543721 is a deficient number, since it is larger than the sum of its proper divisors (582231).

213543721 is an equidigital number, since it uses as much as digits as its factorization.

213543721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 582230.

The product of its digits is 5040, while the sum is 28.

The square root of 213543721 is about 14613.1352214369. The cubic root of 213543721 is about 597.7169917326.

The spelling of 213543721 in words is "two hundred thirteen million, five hundred forty-three thousand, seven hundred twenty-one".