261210531 has 4 divisors (see below), whose sum is σ = 348280712. Its totient is φ = 174140352.

The previous prime is 261210529. The next prime is 261210539. The reversal of 261210531 is 135012162.

261210531 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 not a de Polignac number, because 261210531 - 2¹ = 261210529 is a prime.

It is a super-2 number, since 2×261210531² = 136461883010603922, 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 = 261210498 and 261210507.

It is not an unprimeable number, because it can be changed into a prime (261210539) 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, 43535086 + ... + 43535091.

It is an arithmetic number, because the mean of its divisors is an integer number (87070178).

Almost surely, 2^261210531 is an apocalyptic number.

261210531 is a deficient number, since it is larger than the sum of its proper divisors (87070181).

261210531 is an equidigital number, since it uses as much as digits as its factorization.

261210531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87070180.

The product of its (nonzero) digits is 360, while the sum is 21.

The square root of 261210531 is about 16162.0088788492. The cubic root of 261210531 is about 639.2394375047.

Adding to 261210531 its reverse (135012162), we get a palindrome (396222693).

The spelling of 261210531 in words is "two hundred sixty-one million, two hundred ten thousand, five hundred thirty-one".