61306531 has 16 divisors (see below), whose sum is σ = 73392480. Its totient is φ = 50469120.

The previous prime is 61306517. The next prime is 61306537. The reversal of 61306531 is 13560316.

It is not a de Polignac number, because 61306531 - 2⁹ = 61306019 is a prime.

It is a super-2 number, since 2×61306531² = 7516981486507922, 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 = 61306496 and 61306505.

It is not an unprimeable number, because it can be changed into a prime (61306537) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3535 + ... + 11623.

It is an arithmetic number, because the mean of its divisors is an integer number (4587030).

Almost surely, 2^61306531 is an apocalyptic number.

61306531 is a deficient number, since it is larger than the sum of its proper divisors (12085949).

61306531 is a wasteful number, since it uses less digits than its factorization.

61306531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8166.

The product of its (nonzero) digits is 1620, while the sum is 25.

The square root of 61306531 is about 7829.8487213994. The cubic root of 61306531 is about 394.3079930913.

Adding to 61306531 its reverse (13560316), we get a palindrome (74866847).

The spelling of 61306531 in words is "sixty-one million, three hundred six thousand, five hundred thirty-one".