1211692391361 has 9 divisors (see below), whose sum is σ = 1750227113089. Its totient is φ = 807792726036.

The previous prime is 1211692391353. The next prime is 1211692391387. The reversal of 1211692391361 is 1631932961121.

The square root of 1211692391361 is 1100769.

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

1211692391361 is a `hidden beast` number, since 1 + 2 + 116 + 92 + 3 + 91 + 361 = 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 1211692391361 - 2³ = 1211692391353 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1211692391341) 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, 3118846 + ... + 3485768.

Almost surely, 2^{1211692391361} is an apocalyptic number.

1211692391361 is the 1100769-th square number.

1211692391361 is the 550385-th centered octagonal number.

It is an amenable number.

1211692391361 is a deficient number, since it is larger than the sum of its proper divisors (538534721728).

1211692391361 is an frugal number, since it uses more digits than its factorization.

1211692391361 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 733852 (or 366926 counting only the distinct ones).

The product of its digits is 104976, while the sum is 45.

The spelling of 1211692391361 in words is "one trillion, two hundred eleven billion, six hundred ninety-two million, three hundred ninety-one thousand, three hundred sixty-one".