987555261 has 24 divisors (see below), whose sum is σ = 1670968224. Its totient is φ = 513014880.

The previous prime is 987555253. The next prime is 987555263. The reversal of 987555261 is 162555789.

It is a happy number.

It is not a de Polignac number, because 987555261 - 2³ = 987555253 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 987555261.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (987555263) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 303750 + ... + 306983.

It is an arithmetic number, because the mean of its divisors is an integer number (69623676).

Almost surely, 2^987555261 is an apocalyptic number.

It is an amenable number.

987555261 is a deficient number, since it is larger than the sum of its proper divisors (683412963).

987555261 is a wasteful number, since it uses less digits than its factorization.

987555261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 610761 (or 610754 counting only the distinct ones).

The product of its digits is 756000, while the sum is 48.

The square root of 987555261 is about 31425.3919784623. The cubic root of 987555261 is about 995.8344257515.

The spelling of 987555261 in words is "nine hundred eighty-seven million, five hundred fifty-five thousand, two hundred sixty-one".