61307531 has 4 divisors (see below), whose sum is σ = 61323192. Its totient is φ = 61291872.

The previous prime is 61307513. The next prime is 61307539. The reversal of 61307531 is 13570316.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 61307531 - 2¹⁰ = 61306507 is a prime.

It is a super-2 number, since 2×61307531² = 7517226714631922, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 61307531.

It is not an unprimeable number, because it can be changed into a prime (61307539) 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, 3860 + ... + 11726.

It is an arithmetic number, because the mean of its divisors is an integer number (15330798).

Almost surely, 2^61307531 is an apocalyptic number.

61307531 is a deficient number, since it is larger than the sum of its proper divisors (15661).

61307531 is an equidigital number, since it uses as much as digits as its factorization.

61307531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15660.

The product of its (nonzero) digits is 1890, while the sum is 26.

The square root of 61307531 is about 7829.9125793332. The cubic root of 61307531 is about 394.3101369948.

Adding to 61307531 its reverse (13570316), we get a palindrome (74877847).

The spelling of 61307531 in words is "sixty-one million, three hundred seven thousand, five hundred thirty-one".