561649821489 has 9 divisors (see below), whose sum is σ = 811275211929. Its totient is φ = 374431715460.

The previous prime is 561649821457. The next prime is 561649821493. The reversal of 561649821489 is 984128946165.

The square root of 561649821489 is 749433.

It is a perfect power (a square), and thus also a powerful number.

561649821489 is a `hidden beast` number, since 5 + 6 + 1 + 64 + 98 + 2 + 1 + 489 = 666.

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 561649821489 - 2⁵ = 561649821457 is a prime.

It is not an unprimeable number, because it can be changed into a prime (561649821449) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 2123394 + ... + 2373204.

Almost surely, 2^561649821489 is an apocalyptic number.

561649821489 is the 749433-rd square number.

561649821489 is the 374717-th centered octagonal number.

It is an amenable number.

561649821489 is a deficient number, since it is larger than the sum of its proper divisors (249625390440).

561649821489 is an frugal number, since it uses more digits than its factorization.

561649821489 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 499628 (or 249814 counting only the distinct ones).

The product of its digits is 29859840, while the sum is 63.

The spelling of 561649821489 in words is "five hundred sixty-one billion, six hundred forty-nine million, eight hundred twenty-one thousand, four hundred eighty-nine".