1221026857 has 2 divisors, whose sum is σ = 1221026858. Its totient is φ = 1221026856.

The previous prime is 1221026843. The next prime is 1221026869. The reversal of 1221026857 is 7586201221.

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., 1127885056 + 93141801 = 33584^2 + 9651^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221026857 is a prime.

It is not a weakly prime, because it can be changed into another prime (1221026057) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610513428 + 610513429.

It is an arithmetic number, because the mean of its divisors is an integer number (610513429).

Almost surely, 2^1221026857 is an apocalyptic number.

It is an amenable number.

1221026857 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221026857 is an equidigital number, since it uses as much as digits as its factorization.

1221026857 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13440, while the sum is 34.

The square root of 1221026857 is about 34943.1947165682. The cubic root of 1221026857 is about 1068.8294349403.

The spelling of 1221026857 in words is "one billion, two hundred twenty-one million, twenty-six thousand, eight hundred fifty-seven".