1221533129 has 2 divisors, whose sum is σ = 1221533130. Its totient is φ = 1221533128.

The previous prime is 1221533119. The next prime is 1221533171. The reversal of 1221533129 is 9213351221.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1218010000 + 3523129 = 34900^2 + 1877^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221533129 - 2¹⁶ = 1221467593 is a prime.

It is a super-3 number, since 3×1221533129³ (a number of 28 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (1221533119) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610766564 + 610766565.

It is an arithmetic number, because the mean of its divisors is an integer number (610766565).

Almost surely, 2^1221533129 is an apocalyptic number.

It is an amenable number.

1221533129 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221533129 is an equidigital number, since it uses as much as digits as its factorization.

1221533129 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3240, while the sum is 29.

The square root of 1221533129 is about 34950.4381803719. The cubic root of 1221533129 is about 1068.9771367544.

The spelling of 1221533129 in words is "one billion, two hundred twenty-one million, five hundred thirty-three thousand, one hundred twenty-nine".