1002171521 has 12 divisors (see below), whose sum is σ = 1100070828. Its totient is φ = 912397824.

The previous prime is 1002171517. The next prime is 1002171557. The reversal of 1002171521 is 1251712001.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 93993025 + 908178496 = 9695^2 + 30136^2 .

It is not a de Polignac number, because 1002171521 - 2² = 1002171517 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1002171493 and 1002171502.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1002171421) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 28280 + ... + 52953.

It is an arithmetic number, because the mean of its divisors is an integer number (91672569).

Almost surely, 2^1002171521 is an apocalyptic number.

It is an amenable number.

1002171521 is a deficient number, since it is larger than the sum of its proper divisors (97899307).

1002171521 is an equidigital number, since it uses as much as digits as its factorization.

1002171521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81332 (or 81319 counting only the distinct ones).

The product of its (nonzero) digits is 140, while the sum is 20.

The square root of 1002171521 is about 31657.0927439650. The cubic root of 1002171521 is about 1000.7233170197.

Adding to 1002171521 its reverse (1251712001), we get a palindrome (2253883522).

The spelling of 1002171521 in words is "one billion, two million, one hundred seventy-one thousand, five hundred twenty-one".