1550506221 has 18 divisors (see below), whose sum is σ = 2461732910. Its totient is φ = 939700080.

The previous prime is 1550506213. The next prime is 1550506231. The reversal of 1550506221 is 1226050551.

1550506221 is a `hidden beast` number, since 1 + 550 + 50 + 62 + 2 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 1478018025 + 72488196 = 38445^2 + 8514^2 .

It is not a de Polignac number, because 1550506221 - 2³ = 1550506213 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1550506211) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 710806 + ... + 712983.

Almost surely, 2^1550506221 is an apocalyptic number.

1550506221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1550506221 is a deficient number, since it is larger than the sum of its proper divisors (911226689).

1550506221 is a wasteful number, since it uses less digits than its factorization.

1550506221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1423817 (or 1423803 counting only the distinct ones).

The product of its (nonzero) digits is 3000, while the sum is 27.

The square root of 1550506221 is about 39376.4678583542. The cubic root of 1550506221 is about 1157.4205021073.

Adding to 1550506221 its reverse (1226050551), we get a palindrome (2776556772).

The spelling of 1550506221 in words is "one billion, five hundred fifty million, five hundred six thousand, two hundred twenty-one".