15515455121 has 2 divisors, whose sum is σ = 15515455122. Its totient is φ = 15515455120.

The previous prime is 15515455099. The next prime is 15515455129. The reversal of 15515455121 is 12155451551.

15515455121 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14415604225 + 1099850896 = 120065^2 + 33164^2 .

It is an emirp because it is prime and its reverse (12155451551) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 15515455121 - 2¹⁴ = 15515438737 is a prime.

It is a super-2 number, since 2×15515455121² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (15515455129) 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, 7757727560 + 7757727561.

It is an arithmetic number, because the mean of its divisors is an integer number (7757727561).

Almost surely, 2^15515455121 is an apocalyptic number.

It is an amenable number.

15515455121 is a deficient number, since it is larger than the sum of its proper divisors (1).

15515455121 is an equidigital number, since it uses as much as digits as its factorization.

15515455121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 25000, while the sum is 35.

The spelling of 15515455121 in words is "fifteen billion, five hundred fifteen million, four hundred fifty-five thousand, one hundred twenty-one".