561721567 has 12 divisors (see below), whose sum is σ = 649928440. Its totient is φ = 483777360.

The previous prime is 561721493. The next prime is 561721577. The reversal of 561721567 is 765127165.

It is a happy number.

It is a de Polignac number, because none of the positive numbers 2^k-561721567 is a prime.

It is a super-2 number, since 2×561721567² = 631062237665870978, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (561721577) 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 11 ways as a sum of consecutive naturals, for example, 119868 + ... + 124465.

Almost surely, 2^561721567 is an apocalyptic number.

561721567 is a deficient number, since it is larger than the sum of its proper divisors (88206873).

561721567 is a wasteful number, since it uses less digits than its factorization.

561721567 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 244374 (or 244363 counting only the distinct ones).

The product of its digits is 88200, while the sum is 40.

The square root of 561721567 is about 23700.6659611075. The cubic root of 561721567 is about 825.1008469314.

The spelling of 561721567 in words is "five hundred sixty-one million, seven hundred twenty-one thousand, five hundred sixty-seven".