1539041217561 has 9 divisors (see below), whose sum is σ = 2223064912341. Its totient is φ = 1026024997212.

The previous prime is 1539041217533. The next prime is 1539041217599. The reversal of 1539041217561 is 1657121409351.

The square root of 1539041217561 is 1240581.

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

1539041217561 is a `hidden beast` number, since 1 + 5 + 3 + 9 + 0 + 412 + 175 + 61 = 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 1539041217561 - 2¹³ = 1539041209369 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1539041217361) 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, 3514980 + ... + 3928506.

Almost surely, 2^{1539041217561} is an apocalyptic number.

1539041217561 is the 1240581-st square number.

1539041217561 is the 620291-st centered octagonal number.

It is an amenable number.

1539041217561 is a deficient number, since it is larger than the sum of its proper divisors (684023694780).

1539041217561 is an frugal number, since it uses more digits than its factorization.

1539041217561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 827060 (or 413530 counting only the distinct ones).

The product of its (nonzero) digits is 226800, while the sum is 45.

The spelling of 1539041217561 in words is "one trillion, five hundred thirty-nine billion, forty-one million, two hundred seventeen thousand, five hundred sixty-one".