543786781561 has 9 divisors (see below), whose sum is σ = 545060328399. Its totient is φ = 542516208624.

The previous prime is 543786781543. The next prime is 543786781579. The reversal of 543786781561 is 165187687345.

The square root of 543786781561 is 737419.

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

It is an interprime number because it is at equal distance from previous prime (543786781543) and next prime (543786781579).

It can be written as a sum of positive squares in only one way, i.e., 28630332025 + 515156449536 = 169205^2 + 717744^2 .

It is not a de Polignac number, because 543786781561 - 2¹⁷ = 543786650489 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 543786781561.

It is not an unprimeable number, because it can be changed into a prime (543786784561) 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, 580348285 + ... + 580349221.

It is an arithmetic number, because the mean of its divisors is an integer number (60562258711).

Almost surely, 2^543786781561 is an apocalyptic number.

543786781561 is the 737419-th square number.

543786781561 is the 368710-th centered octagonal number.

It is an amenable number.

543786781561 is a deficient number, since it is larger than the sum of its proper divisors (1273546838).

543786781561 is an frugal number, since it uses more digits than its factorization.

543786781561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3448 (or 1724 counting only the distinct ones).

The product of its digits is 33868800, while the sum is 61.

The spelling of 543786781561 in words is "five hundred forty-three billion, seven hundred eighty-six million, seven hundred eighty-one thousand, five hundred sixty-one".