561121281 has 24 divisors (see below), whose sum is σ = 975049920. Its totient is φ = 303764256.

The previous prime is 561121277. The next prime is 561121291. The reversal of 561121281 is 182121165.

561121281 is a `hidden beast` number, since 5 + 611 + 21 + 28 + 1 = 666.

It is not a de Polignac number, because 561121281 - 2² = 561121277 is a prime.

It is a super-2 number, since 2×561121281² = 629714183982161922, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (561121201) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 233190 + ... + 235583.

It is an arithmetic number, because the mean of its divisors is an integer number (40627080).

Almost surely, 2^561121281 is an apocalyptic number.

It is an amenable number.

561121281 is a deficient number, since it is larger than the sum of its proper divisors (413928639).

561121281 is a wasteful number, since it uses less digits than its factorization.

561121281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 468805 (or 468802 counting only the distinct ones).

The product of its digits is 960, while the sum is 27.

The square root of 561121281 is about 23687.9986702127. The cubic root of 561121281 is about 824.8068263973.

The spelling of 561121281 in words is "five hundred sixty-one million, one hundred twenty-one thousand, two hundred eighty-one".