1221851153 has 2 divisors, whose sum is σ = 1221851154. Its totient is φ = 1221851152.

The previous prime is 1221851131. The next prime is 1221851159. The reversal of 1221851153 is 3511581221.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1221642304 + 208849 = 34952^2 + 457^2 .

It is an emirp because it is prime and its reverse (3511581221) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1221851153 - 2¹⁴ = 1221834769 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (1221851159) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610925576 + 610925577.

It is an arithmetic number, because the mean of its divisors is an integer number (610925577).

Almost surely, 2^1221851153 is an apocalyptic number.

It is an amenable number.

1221851153 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221851153 is an equidigital number, since it uses as much as digits as its factorization.

1221851153 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2400, while the sum is 29.

The square root of 1221851153 is about 34954.9875268180. The cubic root of 1221851153 is about 1069.0698974768.

The spelling of 1221851153 in words is "one billion, two hundred twenty-one million, eight hundred fifty-one thousand, one hundred fifty-three".