15551505055621 has 2 divisors, whose sum is σ = 15551505055622. Its totient is φ = 15551505055620.

The previous prime is 15551505055607. The next prime is 15551505055643. The reversal of 15551505055621 is 12655050515551.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12756940882596 + 2794564173025 = 3571686^2 + 1671695^2 .

It is a cyclic number.

It is not a de Polignac number, because 15551505055621 - 2²¹ = 15551502958469 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15551506055621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7775752527810 + 7775752527811.

It is an arithmetic number, because the mean of its divisors is an integer number (7775752527811).

Almost surely, 2^{15551505055621} is an apocalyptic number.

It is an amenable number.

15551505055621 is a deficient number, since it is larger than the sum of its proper divisors (1).

15551505055621 is an equidigital number, since it uses as much as digits as its factorization.

15551505055621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 937500, while the sum is 46.

The spelling of 15551505055621 in words is "fifteen trillion, five hundred fifty-one billion, five hundred five million, fifty-five thousand, six hundred twenty-one".