23121315551 has 2 divisors, whose sum is σ = 23121315552. Its totient is φ = 23121315550.

The previous prime is 23121315533. The next prime is 23121315601. The reversal of 23121315551 is 15551312132.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-23121315551 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (23121315751) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11560657775 + 11560657776.

It is an arithmetic number, because the mean of its divisors is an integer number (11560657776).

Almost surely, 2^23121315551 is an apocalyptic number.

23121315551 is a deficient number, since it is larger than the sum of its proper divisors (1).

23121315551 is an equidigital number, since it uses as much as digits as its factorization.

23121315551 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4500, while the sum is 29.

Adding to 23121315551 its reverse (15551312132), we get a palindrome (38672627683).

The spelling of 23121315551 in words is "twenty-three billion, one hundred twenty-one million, three hundred fifteen thousand, five hundred fifty-one".