561994261 has 4 divisors (see below), whose sum is σ = 563298624. Its totient is φ = 560689900.

The previous prime is 561994253. The next prime is 561994267. The reversal of 561994261 is 162499165.

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 561994261 - 2³ = 561994253 is a prime.

It is a super-2 number, since 2×561994261² = 631675098793872242, 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 (561994267) 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, 651535 + ... + 652396.

It is an arithmetic number, because the mean of its divisors is an integer number (140824656).

Almost surely, 2^561994261 is an apocalyptic number.

It is an amenable number.

561994261 is a deficient number, since it is larger than the sum of its proper divisors (1304363).

561994261 is a wasteful number, since it uses less digits than its factorization.

561994261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1304362.

The product of its digits is 116640, while the sum is 43.

The square root of 561994261 is about 23706.4181393985. The cubic root of 561994261 is about 825.2343434676.

The spelling of 561994261 in words is "five hundred sixty-one million, nine hundred ninety-four thousand, two hundred sixty-one".