1211235551 has 2 divisors, whose sum is σ = 1211235552. Its totient is φ = 1211235550.

The previous prime is 1211235539. The next prime is 1211235593. The reversal of 1211235551 is 1555321121.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1211235551 - 2¹⁴ = 1211219167 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1211235551.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1211235521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605617775 + 605617776.

It is an arithmetic number, because the mean of its divisors is an integer number (605617776).

Almost surely, 2^1211235551 is an apocalyptic number.

1211235551 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211235551 is an equidigital number, since it uses as much as digits as its factorization.

1211235551 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1500, while the sum is 26.

The square root of 1211235551 is about 34802.8095273930. The cubic root of 1211235551 is about 1065.9648147356.

Adding to 1211235551 its reverse (1555321121), we get a palindrome (2766556672).

The spelling of 1211235551 in words is "one billion, two hundred eleven million, two hundred thirty-five thousand, five hundred fifty-one".