1221010181 has 2 divisors, whose sum is σ = 1221010182. Its totient is φ = 1221010180.

The previous prime is 1221010123. The next prime is 1221010199. The reversal of 1221010181 is 1810101221.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 707081281 + 513928900 = 26591^2 + 22670^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221010181 - 2⁶ = 1221010117 is a prime.

It is a super-2 number, since 2×1221010181² = 2981731724211305522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221010111) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610505090 + 610505091.

It is an arithmetic number, because the mean of its divisors is an integer number (610505091).

Almost surely, 2^1221010181 is an apocalyptic number.

It is an amenable number.

1221010181 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221010181 is an equidigital number, since it uses as much as digits as its factorization.

1221010181 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 32, while the sum is 17.

The square root of 1221010181 is about 34942.9560999066. The cubic root of 1221010181 is about 1068.8245691230.

The spelling of 1221010181 in words is "one billion, two hundred twenty-one million, ten thousand, one hundred eighty-one".