61531 has 4 divisors (see below), whose sum is σ = 63232. Its totient is φ = 59832.

The previous prime is 61519. The next prime is 61543. The reversal of 61531 is 13516.

61531 is nontrivially palindromic in base 6.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (61519) and next prime (61543).

It is a cyclic number.

It is not a de Polignac number, because 61531 - 2⁷ = 61403 is a prime.

It is a super-2 number, since 2×61531² = 7572127922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61511) 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, 795 + ... + 868.

It is an arithmetic number, because the mean of its divisors is an integer number (15808).

2⁶¹⁵³¹ is an apocalyptic number.

61531 is a deficient number, since it is larger than the sum of its proper divisors (1701).

61531 is a wasteful number, since it uses less digits than its factorization.

61531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1700.

The product of its digits is 90, while the sum is 16.

The square root of 61531 is about 248.0544295109. The cubic root of 61531 is about 39.4788649419.

It can be divided in two parts, 615 and 31, that added together give a palindrome (646).

The spelling of 61531 in words is "sixty-one thousand, five hundred thirty-one".