1761165213921 has 9 divisors (see below), whose sum is σ = 2543911059729. Its totient is φ = 1174107488436.

The previous prime is 1761165213919. The next prime is 1761165213953. The reversal of 1761165213921 is 1293125611671.

The square root of 1761165213921 is 1327089.

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

1761165213921 is a `hidden beast` number, since 1 + 7 + 6 + 116 + 521 + 3 + 9 + 2 + 1 = 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 1761165213921 - 2¹ = 1761165213919 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1761165213991) 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, 3760086 + ... + 4202448.

Almost surely, 2^{1761165213921} is an apocalyptic number.

1761165213921 is the 1327089-th square number.

1761165213921 is the 663545-th centered octagonal number.

It is an amenable number.

1761165213921 is a deficient number, since it is larger than the sum of its proper divisors (782745845808).

1761165213921 is an frugal number, since it uses more digits than its factorization.

1761165213921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 884732 (or 442366 counting only the distinct ones).

The product of its digits is 136080, while the sum is 45.

The spelling of 1761165213921 in words is "one trillion, seven hundred sixty-one billion, one hundred sixty-five million, two hundred thirteen thousand, nine hundred twenty-one".