15550020 has 36 divisors (see below), whose sum is σ = 47168940. Its totient is φ = 4146624.

The previous prime is 15550009. The next prime is 15550021. The reversal of 15550020 is 2005551.

It can be written as a sum of positive squares in 2 ways, for example, as 2762244 + 12787776 = 1662^2 + 3576^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 15549975 and 15550002.

It is not an unprimeable number, because it can be changed into a prime (15550021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 43015 + ... + 43374.

Almost surely, 2^15550020 is an apocalyptic number.

15550020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

15550020 is an abundant number, since it is smaller than the sum of its proper divisors (31618920).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

15550020 is a wasteful number, since it uses less digits than its factorization.

15550020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 86404 (or 86399 counting only the distinct ones).

The product of its (nonzero) digits is 250, while the sum is 18.

The square root of 15550020 is about 3943.3513665409. The cubic root of 15550020 is about 249.5994652972.

Adding to 15550020 its reverse (2005551), we get a palindrome (17555571).

The spelling of 15550020 in words is "fifteen million, five hundred fifty thousand, twenty".