213638491 has 8 divisors (see below), whose sum is σ = 238480704. Its totient is φ = 189699720.

The previous prime is 213638479. The next prime is 213638497. The reversal of 213638491 is 194836312.

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

It is a cyclic number.

It is not a de Polignac number, because 213638491 - 2⁵ = 213638459 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 213638491.

It is not an unprimeable number, because it can be changed into a prime (213638497) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 225361 + ... + 226306.

It is an arithmetic number, because the mean of its divisors is an integer number (29810088).

Almost surely, 2^213638491 is an apocalyptic number.

213638491 is a deficient number, since it is larger than the sum of its proper divisors (24842213).

213638491 is a wasteful number, since it uses less digits than its factorization.

213638491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 451721.

The product of its digits is 31104, while the sum is 37.

The square root of 213638491 is about 14616.3774923885. The cubic root of 213638491 is about 597.8054002661.

The spelling of 213638491 in words is "two hundred thirteen million, six hundred thirty-eight thousand, four hundred ninety-one".