961506581 has 4 divisors (see below), whose sum is σ = 1098864672. Its totient is φ = 824148492.

The previous prime is 961506527. The next prime is 961506593. The reversal of 961506581 is 185605169.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 961506581 - 2¹⁸ = 961244437 is a prime.

It is a super-2 number, since 2×961506581² = 1848989810612619122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (961506181) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 68679035 + ... + 68679048.

It is an arithmetic number, because the mean of its divisors is an integer number (274716168).

Almost surely, 2^961506581 is an apocalyptic number.

It is an amenable number.

961506581 is a deficient number, since it is larger than the sum of its proper divisors (137358091).

961506581 is a wasteful number, since it uses less digits than its factorization.

961506581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 137358090.

The product of its (nonzero) digits is 64800, while the sum is 41.

The square root of 961506581 is about 31008.1695848046. The cubic root of 961506581 is about 987.0006083814. Note that the first 3 decimals are identical.

The spelling of 961506581 in words is "nine hundred sixty-one million, five hundred six thousand, five hundred eighty-one".