121553243551 has 2 divisors, whose sum is σ = 121553243552. Its totient is φ = 121553243550.

The previous prime is 121553243507. The next prime is 121553243633. The reversal of 121553243551 is 155342355121.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 121553243551 - 2¹¹ = 121553241503 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 121553243551.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (121553243051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60776621775 + 60776621776.

It is an arithmetic number, because the mean of its divisors is an integer number (60776621776).

Almost surely, 2^121553243551 is an apocalyptic number.

121553243551 is a deficient number, since it is larger than the sum of its proper divisors (1).

121553243551 is an equidigital number, since it uses as much as digits as its factorization.

121553243551 is an evil number, because the sum of its binary digits is even.

The product of its digits is 90000, while the sum is 37.

Adding to 121553243551 its reverse (155342355121), we get a palindrome (276895598672).

The spelling of 121553243551 in words is "one hundred twenty-one billion, five hundred fifty-three million, two hundred forty-three thousand, five hundred fifty-one".