213657631 has 4 divisors (see below), whose sum is σ = 233081064. Its totient is φ = 194234200.

The previous prime is 213657607. The next prime is 213657643. The reversal of 213657631 is 136756312.

213657631 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 213657631 - 2¹¹ = 213655583 is a prime.

It is a super-2 number, since 2×213657631² = 91299166569064322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213457631) 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, 9711700 + ... + 9711721.

It is an arithmetic number, because the mean of its divisors is an integer number (58270266).

Almost surely, 2^213657631 is an apocalyptic number.

213657631 is a deficient number, since it is larger than the sum of its proper divisors (19423433).

213657631 is a wasteful number, since it uses less digits than its factorization.

213657631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19423432.

The product of its digits is 22680, while the sum is 34.

The square root of 213657631 is about 14617.0322227188. The cubic root of 213657631 is about 597.8232523139.

The spelling of 213657631 in words is "two hundred thirteen million, six hundred fifty-seven thousand, six hundred thirty-one".