987398561 has 4 divisors (see below), whose sum is σ = 987867972. Its totient is φ = 986929152.

The previous prime is 987398543. The next prime is 987398567. The reversal of 987398561 is 165893789.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 165893789 = 509 ⋅325921.

It can be written as a sum of positive squares in 2 ways, for example, as 10523536 + 976875025 = 3244^2 + 31255^2 .

It is a cyclic number.

It is not a de Polignac number, because 987398561 - 2¹⁸ = 987136417 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 987398497 and 987398506.

It is not an unprimeable number, because it can be changed into a prime (987398567) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 231536 + ... + 235761.

It is an arithmetic number, because the mean of its divisors is an integer number (246966993).

Almost surely, 2^987398561 is an apocalyptic number.

It is an amenable number.

987398561 is a deficient number, since it is larger than the sum of its proper divisors (469411).

987398561 is a wasteful number, since it uses less digits than its factorization.

987398561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 469410.

The product of its digits is 3265920, while the sum is 56.

The square root of 987398561 is about 31422.8986727832. The cubic root of 987398561 is about 995.7817517342.

The spelling of 987398561 in words is "nine hundred eighty-seven million, three hundred ninety-eight thousand, five hundred sixty-one".