213403991 has 4 divisors (see below), whose sum is σ = 224635800. Its totient is φ = 202172184.

The previous prime is 213403987. The next prime is 213403999. The reversal of 213403991 is 199304312.

213403991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 213403991 - 2² = 213403987 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 (213403999) 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, 5615876 + ... + 5615913.

It is an arithmetic number, because the mean of its divisors is an integer number (56158950).

Almost surely, 2^213403991 is an apocalyptic number.

213403991 is a deficient number, since it is larger than the sum of its proper divisors (11231809).

213403991 is a wasteful number, since it uses less digits than its factorization.

213403991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11231808.

The product of its (nonzero) digits is 5832, while the sum is 32.

The square root of 213403991 is about 14608.3534664246. The cubic root of 213403991 is about 597.5865934265.

The spelling of 213403991 in words is "two hundred thirteen million, four hundred three thousand, nine hundred ninety-one".