213540391 has 4 divisors (see below), whose sum is σ = 213580984. Its totient is φ = 213499800.

The previous prime is 213540367. The next prime is 213540401. The reversal of 213540391 is 193045312.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 213540391 - 2²⁵ = 179985959 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213540191) 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, 10980 + ... + 23401.

It is an arithmetic number, because the mean of its divisors is an integer number (53395246).

Almost surely, 2^213540391 is an apocalyptic number.

213540391 is a deficient number, since it is larger than the sum of its proper divisors (40593).

213540391 is an equidigital number, since it uses as much as digits as its factorization.

213540391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40592.

The product of its (nonzero) digits is 3240, while the sum is 28.

The square root of 213540391 is about 14613.0212824043. The cubic root of 213540391 is about 597.7138847842.

The spelling of 213540391 in words is "two hundred thirteen million, five hundred forty thousand, three hundred ninety-one".