1221093510961 has 9 divisors (see below), whose sum is σ = 1239665969451. Its totient is φ = 1202795302632.

The previous prime is 1221093510947. The next prime is 1221093511019. The reversal of 1221093510961 is 1690153901221.

The square root of 1221093510961 is 1105031.

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

It can be written as a sum of positive squares in only one way, i.e., 33089429025 + 1188004081936 = 181905^2 + 1089956^2 .

It is not a de Polignac number, because 1221093510961 - 2⁵ = 1221093510929 is a prime.

It is a super-2 number, since 2×1221093510961² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221093510911) 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, 74028831 + ... + 74045323.

Almost surely, 2^{1221093510961} is an apocalyptic number.

1221093510961 is the 1105031-st square number.

1221093510961 is the 552516-th centered octagonal number.

It is an amenable number.

1221093510961 is a deficient number, since it is larger than the sum of its proper divisors (18572458490).

1221093510961 is an frugal number, since it uses more digits than its factorization.

1221093510961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33120 (or 16560 counting only the distinct ones).

The product of its (nonzero) digits is 29160, while the sum is 40.

The spelling of 1221093510961 in words is "one trillion, two hundred twenty-one billion, ninety-three million, five hundred ten thousand, nine hundred sixty-one".