1521201321 has 6 divisors (see below), whose sum is σ = 2197290810. Its totient is φ = 1014134208.

The previous prime is 1521201257. The next prime is 1521201343. The reversal of 1521201321 is 1231021251.

It can be written as a sum of positive squares in only one way, i.e., 1325760921 + 195440400 = 36411^2 + 13980^2 .

It is not a de Polignac number, because 1521201321 - 2⁶ = 1521201257 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1521201294 and 1521201303.

It is not an unprimeable number, because it can be changed into a prime (1521201391) 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, 84511176 + ... + 84511193.

It is an arithmetic number, because the mean of its divisors is an integer number (366215135).

Almost surely, 2^1521201321 is an apocalyptic number.

It is an amenable number.

1521201321 is a deficient number, since it is larger than the sum of its proper divisors (676089489).

1521201321 is a wasteful number, since it uses less digits than its factorization.

1521201321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 169022375 (or 169022372 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 18.

The square root of 1521201321 is about 39002.5809530600. The cubic root of 1521201321 is about 1150.0822426375.

Adding to 1521201321 its reverse (1231021251), we get a palindrome (2752222572).

The spelling of 1521201321 in words is "one billion, five hundred twenty-one million, two hundred one thousand, three hundred twenty-one".