55121070721 has 2 divisors, whose sum is σ = 55121070722. Its totient is φ = 55121070720.

The previous prime is 55121070713. The next prime is 55121070743. The reversal of 55121070721 is 12707012155.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 47489126400 + 7631944321 = 217920^2 + 87361^2 .

It is a cyclic number.

It is not a de Polignac number, because 55121070721 - 2³ = 55121070713 is a prime.

It is not a weakly prime, because it can be changed into another prime (55121070701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27560535360 + 27560535361.

It is an arithmetic number, because the mean of its divisors is an integer number (27560535361).

Almost surely, 2^55121070721 is an apocalyptic number.

It is an amenable number.

55121070721 is a deficient number, since it is larger than the sum of its proper divisors (1).

55121070721 is an equidigital number, since it uses as much as digits as its factorization.

55121070721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4900, while the sum is 31.

Adding to 55121070721 its reverse (12707012155), we get a palindrome (67828082876).

The spelling of 55121070721 in words is "fifty-five billion, one hundred twenty-one million, seventy thousand, seven hundred twenty-one".