15550121 has 4 divisors (see below), whose sum is σ = 16464852. Its totient is φ = 14635392.

The previous prime is 15550103. The next prime is 15550141. The reversal of 15550121 is 12105551.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4791721 + 10758400 = 2189^2 + 3280^2 .

It is a cyclic number.

It is not a de Polignac number, because 15550121 - 2¹⁰ = 15549097 is a prime.

It is a super-2 number, since 2×15550121² = 483612526229282, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 15550093 and 15550102.

It is not an unprimeable number, because it can be changed into a prime (15550141) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 457340 + ... + 457373.

It is an arithmetic number, because the mean of its divisors is an integer number (4116213).

Almost surely, 2^15550121 is an apocalyptic number.

It is an amenable number.

15550121 is a deficient number, since it is larger than the sum of its proper divisors (914731).

15550121 is an equidigital number, since it uses as much as digits as its factorization.

15550121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 914730.

The product of its (nonzero) digits is 250, while the sum is 20.

The square root of 15550121 is about 3943.3641728859. The cubic root of 15550121 is about 249.6000056929.

Adding to 15550121 its reverse (12105551), we get a palindrome (27655672).

The spelling of 15550121 in words is "fifteen million, five hundred fifty thousand, one hundred twenty-one".