1521989 has 12 divisors (see below), whose sum is σ = 1795500. Its totient is φ = 1286208.

The previous prime is 1521983. The next prime is 1521991. The reversal of 1521989 is 9891251.

It can be written as a sum of positive squares in 2 ways, for example, as 693889 + 828100 = 833^2 + 910^2 .

It is not a de Polignac number, because 1521989 - 2⁴ = 1521973 is a prime.

It is a super-2 number, since 2×1521989² = 4632901032242, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1521983) 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, 4187 + ... + 4535.

It is an arithmetic number, because the mean of its divisors is an integer number (149625).

2^1521989 is an apocalyptic number.

It is an amenable number.

1521989 is a deficient number, since it is larger than the sum of its proper divisors (273511).

1521989 is an equidigital number, since it uses as much as digits as its factorization.

1521989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 452 (or 445 counting only the distinct ones).

The product of its digits is 6480, while the sum is 35.

The square root of 1521989 is about 1233.6891828982. The cubic root of 1521989 is about 115.0280712821.

The spelling of 1521989 in words is "one million, five hundred twenty-one thousand, nine hundred eighty-nine".