1221020069 has 2 divisors, whose sum is σ = 1221020070. Its totient is φ = 1221020068.

The previous prime is 1221019979. The next prime is 1221020077. The reversal of 1221020069 is 9600201221.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1218917569 + 2102500 = 34913^2 + 1450^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221020069 is a prime.

It is a super-2 number, since 2×1221020069² = 2981780017801529522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221020569) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610510034 + 610510035.

It is an arithmetic number, because the mean of its divisors is an integer number (610510035).

Almost surely, 2^1221020069 is an apocalyptic number.

It is an amenable number.

1221020069 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221020069 is an equidigital number, since it uses as much as digits as its factorization.

1221020069 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 1221020069 is about 34943.0975873634. The cubic root of 1221020069 is about 1068.8274543048.

The spelling of 1221020069 in words is "one billion, two hundred twenty-one million, twenty thousand, sixty-nine".