1221020873 has 2 divisors, whose sum is σ = 1221020874. Its totient is φ = 1221020872.

The previous prime is 1221020851. The next prime is 1221020887. The reversal of 1221020873 is 3780201221.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1001595904 + 219424969 = 31648^2 + 14813^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221020873 - 2⁶ = 1221020809 is a prime.

It is not a weakly prime, because it can be changed into another prime (1221020893) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610510436 + 610510437.

It is an arithmetic number, because the mean of its divisors is an integer number (610510437).

Almost surely, 2^1221020873 is an apocalyptic number.

It is an amenable number.

1221020873 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221020873 is an equidigital number, since it uses as much as digits as its factorization.

1221020873 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1344, while the sum is 26.

The square root of 1221020873 is about 34943.1090917795. The cubic root of 1221020873 is about 1068.8276889002.

The spelling of 1221020873 in words is "one billion, two hundred twenty-one million, twenty thousand, eight hundred seventy-three".