121211551 has 2 divisors, whose sum is σ = 121211552. Its totient is φ = 121211550.

The previous prime is 121211459. The next prime is 121211557. The reversal of 121211551 is 155112121.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 121211551 - 2¹¹ = 121209503 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (121211557) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60605775 + 60605776.

It is an arithmetic number, because the mean of its divisors is an integer number (60605776).

Almost surely, 2^121211551 is an apocalyptic number.

121211551 is a deficient number, since it is larger than the sum of its proper divisors (1).

121211551 is an equidigital number, since it uses as much as digits as its factorization.

121211551 is an evil number, because the sum of its binary digits is even.

The product of its digits is 100, while the sum is 19.

The square root of 121211551 is about 11009.6117551892. The cubic root of 121211551 is about 494.8968271181.

Adding to 121211551 its reverse (155112121), we get a palindrome (276323672).

The spelling of 121211551 in words is "one hundred twenty-one million, two hundred eleven thousand, five hundred fifty-one".