213257531 has 4 divisors (see below), whose sum is σ = 217281312. Its totient is φ = 209233752.

The previous prime is 213257521. The next prime is 213257543. The reversal of 213257531 is 135752312.

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 213257531 - 2⁶ = 213257467 is a prime.

It is a super-2 number, since 2×213257531² = 90957549056431922, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 213257494 and 213257503.

It is not an unprimeable number, because it can be changed into a prime (213257521) 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, 2011811 + ... + 2011916.

It is an arithmetic number, because the mean of its divisors is an integer number (54320328).

Almost surely, 2^213257531 is an apocalyptic number.

213257531 is a deficient number, since it is larger than the sum of its proper divisors (4023781).

213257531 is an equidigital number, since it uses as much as digits as its factorization.

213257531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4023780.

The product of its digits is 6300, while the sum is 29.

The square root of 213257531 is about 14603.3397207625. The cubic root of 213257531 is about 597.4498534620.

The spelling of 213257531 in words is "two hundred thirteen million, two hundred fifty-seven thousand, five hundred thirty-one".