1521987 has 4 divisors (see below), whose sum is σ = 2029320. Its totient is φ = 1014656.

The previous prime is 1521983. The next prime is 1521991. The reversal of 1521987 is 7891251.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (1521983) and next prime (1521991).

It is a cyclic number.

It is not a de Polignac number, because 1521987 - 2² = 1521983 is a prime.

It is a D-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 3 ways as a sum of consecutive naturals, for example, 253662 + ... + 253667.

It is an arithmetic number, because the mean of its divisors is an integer number (507330).

2^1521987 is an apocalyptic number.

1521987 is a deficient number, since it is larger than the sum of its proper divisors (507333).

1521987 is an equidigital number, since it uses as much as digits as its factorization.

1521987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 507332.

The product of its digits is 5040, while the sum is 33.

The square root of 1521987 is about 1233.6883723210. The cubic root of 1521987 is about 115.0280208971.

The spelling of 1521987 in words is "one million, five hundred twenty-one thousand, nine hundred eighty-seven".