1211723951461 has 4 divisors (see below), whose sum is σ = 1215546424812. Its totient is φ = 1207901478112.

The previous prime is 1211723951441. The next prime is 1211723951507. The reversal of 1211723951461 is 1641593271121.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 405984334561 + 805739616900 = 637169^2 + 897630^2 .

It is a cyclic number.

It is not a de Polignac number, because 1211723951461 - 2⁵ = 1211723951429 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211723951401) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1911236200 + ... + 1911236833.

It is an arithmetic number, because the mean of its divisors is an integer number (303886606203).

Almost surely, 2^{1211723951461} is an apocalyptic number.

It is an amenable number.

1211723951461 is a deficient number, since it is larger than the sum of its proper divisors (3822473351).

1211723951461 is an equidigital number, since it uses as much as digits as its factorization.

1211723951461 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3822473350.

The product of its digits is 90720, while the sum is 43.

The spelling of 1211723951461 in words is "one trillion, two hundred eleven billion, seven hundred twenty-three million, nine hundred fifty-one thousand, four hundred sixty-one".