2221506521 has 6 divisors (see below), whose sum is σ = 2405536830. Its totient is φ = 2050621248.

The previous prime is 2221506499. The next prime is 2221506533. The reversal of 2221506521 is 1256051222.

It can be written as a sum of positive squares in 3 ways, for example, as 136305625 + 2085200896 = 11675^2 + 45664^2 .

It is not a de Polignac number, because 2221506521 - 2¹⁰ = 2221505497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2221506541) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6572336 + ... + 6572673.

It is an arithmetic number, because the mean of its divisors is an integer number (400922805).

Almost surely, 2^2221506521 is an apocalyptic number.

It is an amenable number.

2221506521 is a deficient number, since it is larger than the sum of its proper divisors (184030309).

2221506521 is a wasteful number, since it uses less digits than its factorization.

2221506521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13145035 (or 13145022 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 26.

The square root of 2221506521 is about 47132.8603099791. The cubic root of 2221506521 is about 1304.8157715694.

Adding to 2221506521 its reverse (1256051222), we get a palindrome (3477557743).

The spelling of 2221506521 in words is "two billion, two hundred twenty-one million, five hundred six thousand, five hundred twenty-one".