15551015521 has 2 divisors, whose sum is σ = 15551015522. Its totient is φ = 15551015520.

The previous prime is 15551015509. The next prime is 15551015533. The reversal of 15551015521 is 12551015551.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (15551015509) and next prime (15551015533).

It can be written as a sum of positive squares in only one way, i.e., 10021011025 + 5530004496 = 100105^2 + 74364^2 .

It is a cyclic number.

It is not a de Polignac number, because 15551015521 - 2¹¹ = 15551013473 is a prime.

It is not a weakly prime, because it can be changed into another prime (15551015561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7775507760 + 7775507761.

It is an arithmetic number, because the mean of its divisors is an integer number (7775507761).

Almost surely, 2^15551015521 is an apocalyptic number.

It is an amenable number.

15551015521 is a deficient number, since it is larger than the sum of its proper divisors (1).

15551015521 is an equidigital number, since it uses as much as digits as its factorization.

15551015521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6250, while the sum is 31.

The spelling of 15551015521 in words is "fifteen billion, five hundred fifty-one million, fifteen thousand, five hundred twenty-one".