1221755568973 has 2 divisors, whose sum is σ = 1221755568974. Its totient is φ = 1221755568972.

The previous prime is 1221755568941. The next prime is 1221755568983. The reversal of 1221755568973 is 3798655571221.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1068500544489 + 153255024484 = 1033683^2 + 391478^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221755568973 - 2⁵ = 1221755568941 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221755568923) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610877784486 + 610877784487.

It is an arithmetic number, because the mean of its divisors is an integer number (610877784487).

Almost surely, 2^{1221755568973} is an apocalyptic number.

It is an amenable number.

1221755568973 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221755568973 is an equidigital number, since it uses as much as digits as its factorization.

1221755568973 is an evil number, because the sum of its binary digits is even.

The product of its digits is 31752000, while the sum is 61.

The spelling of 1221755568973 in words is "one trillion, two hundred twenty-one billion, seven hundred fifty-five million, five hundred sixty-eight thousand, nine hundred seventy-three".