987621 has 4 divisors (see below), whose sum is σ = 1316832. Its totient is φ = 658412.

The previous prime is 987607. The next prime is 987631. The reversal of 987621 is 126789.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 987621 - 2¹⁰ = 986597 is a prime.

It is a D-number.

It is a Curzon number.

It is a nialpdrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (987631) 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, 164601 + ... + 164606.

It is an arithmetic number, because the mean of its divisors is an integer number (329208).

2⁹⁸⁷⁶²¹ is an apocalyptic number.

It is an amenable number.

987621 is a deficient number, since it is larger than the sum of its proper divisors (329211).

987621 is a wasteful number, since it uses less digits than its factorization.

987621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 329210.

The product of its digits is 6048, while the sum is 33.

The square root of 987621 is about 993.7912255600. The cubic root of 987621 is about 99.5856521969.

The spelling of 987621 in words is "nine hundred eighty-seven thousand, six hundred twenty-one".