1387521 has 12 divisors (see below), whose sum is σ = 2091648. Its totient is φ = 884664.

The previous prime is 1387517. The next prime is 1387531. The reversal of 1387521 is 1257831.

1387521 is a `hidden beast` number, since 138 + 7 + 521 = 666.

It is not a de Polignac number, because 1387521 - 2² = 1387517 is a prime.

It is a Smith number, since the sum of its digits (27) coincides with the sum of the digits of its prime factors.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1387501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3145 + ... + 3558.

It is an arithmetic number, because the mean of its divisors is an integer number (174304).

2^1387521 is an apocalyptic number.

It is an amenable number.

1387521 is a deficient number, since it is larger than the sum of its proper divisors (704127).

1387521 is a wasteful number, since it uses less digits than its factorization.

1387521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6732 (or 6729 counting only the distinct ones).

The product of its digits is 1680, while the sum is 27.

The square root of 1387521 is about 1177.9308129088. The cubic root of 1387521 is about 111.5355179198.

The spelling of 1387521 in words is "one million, three hundred eighty-seven thousand, five hundred twenty-one".