531155561 has 8 divisors (see below), whose sum is σ = 549753480. Its totient is φ = 512576512.

The previous prime is 531155543. The next prime is 531155567. The reversal of 531155561 is 165551135.

It can be written as a sum of positive squares in 4 ways, for example, as 62173225 + 468982336 = 7885^2 + 21656^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-531155561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (531155567) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 76511 + ... + 83163.

It is an arithmetic number, because the mean of its divisors is an integer number (68719185).

Almost surely, 2^531155561 is an apocalyptic number.

It is an amenable number.

531155561 is a deficient number, since it is larger than the sum of its proper divisors (18597919).

531155561 is a wasteful number, since it uses less digits than its factorization.

531155561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9435.

The product of its digits is 11250, while the sum is 32.

The square root of 531155561 is about 23046.8123826268. The cubic root of 531155561 is about 809.8549559931.

The spelling of 531155561 in words is "five hundred thirty-one million, one hundred fifty-five thousand, five hundred sixty-one".