987717551 has 16 divisors (see below), whose sum is σ = 1023172608. Its totient is φ = 953013600.

The previous prime is 987717509. The next prime is 987717559. The reversal of 987717551 is 155717789.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-987717551 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 987717551.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (987717559) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1565006 + ... + 1565636.

It is an arithmetic number, because the mean of its divisors is an integer number (63948288).

Almost surely, 2^987717551 is an apocalyptic number.

987717551 is the 25661-st pentagonal number.

987717551 is a deficient number, since it is larger than the sum of its proper divisors (35455057).

987717551 is a wasteful number, since it uses less digits than its factorization.

987717551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1142.

The product of its digits is 617400, while the sum is 50.

The square root of 987717551 is about 31427.9740199714. The cubic root of 987717551 is about 995.8889729495. Note that the first 3 decimals are identical.

The spelling of 987717551 in words is "nine hundred eighty-seven million, seven hundred seventeen thousand, five hundred fifty-one".