987238781 has 2 divisors, whose sum is σ = 987238782. Its totient is φ = 987238780.

The previous prime is 987238751. The next prime is 987238783. The reversal of 987238781 is 187832789.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 783720025 + 203518756 = 27995^2 + 14266^2 .

It is a cyclic number.

It is not a de Polignac number, because 987238781 - 2⁶ = 987238717 is a prime.

It is a super-2 number, since 2×987238781² = 1949280821420731922, which contains 22 as substring.

Together with 987238783, it forms a pair of twin primes.

It is a Chen prime.

It is an alternating number because its digits alternate between odd and even.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (987238783) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 493619390 + 493619391.

It is an arithmetic number, because the mean of its divisors is an integer number (493619391).

Almost surely, 2^987238781 is an apocalyptic number.

It is an amenable number.

987238781 is a deficient number, since it is larger than the sum of its proper divisors (1).

987238781 is an equidigital number, since it uses as much as digits as its factorization.

987238781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1354752, while the sum is 53.

The square root of 987238781 is about 31420.3561564792. The cubic root of 987238781 is about 995.7280366498.

The spelling of 987238781 in words is "nine hundred eighty-seven million, two hundred thirty-eight thousand, seven hundred eighty-one".