1221231395869 has 2 divisors, whose sum is σ = 1221231395870. Its totient is φ = 1221231395868.

The previous prime is 1221231395863. The next prime is 1221231395873. The reversal of 1221231395869 is 9685931321221.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1179747890244 + 41483505625 = 1086162^2 + 203675^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221231395869 - 2³³ = 1212641461277 is a prime.

It is a super-2 number, since 2×1221231395869² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221231395863) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610615697934 + 610615697935.

It is an arithmetic number, because the mean of its divisors is an integer number (610615697935).

Almost surely, 2^{1221231395869} is an apocalyptic number.

It is an amenable number.

1221231395869 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221231395869 is an equidigital number, since it uses as much as digits as its factorization.

1221231395869 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1399680, while the sum is 52.

The spelling of 1221231395869 in words is "one trillion, two hundred twenty-one billion, two hundred thirty-one million, three hundred ninety-five thousand, eight hundred sixty-nine".