87550781 has 2 divisors, whose sum is σ = 87550782. Its totient is φ = 87550780.

The previous prime is 87550777. The next prime is 87550787. The reversal of 87550781 is 18705578.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 58767556 + 28783225 = 7666^2 + 5365^2 .

It is a cyclic number.

It is not a de Polignac number, because 87550781 - 2² = 87550777 is a prime.

It is a super-2 number, since 2×87550781² = 15330278507419922, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (87550787) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43775390 + 43775391.

It is an arithmetic number, because the mean of its divisors is an integer number (43775391).

Almost surely, 2^87550781 is an apocalyptic number.

It is an amenable number.

87550781 is a deficient number, since it is larger than the sum of its proper divisors (1).

87550781 is an equidigital number, since it uses as much as digits as its factorization.

87550781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 78400, while the sum is 41.

The square root of 87550781 is about 9356.8574318518. The cubic root of 87550781 is about 444.0378674112.

The spelling of 87550781 in words is "eighty-seven million, five hundred fifty thousand, seven hundred eighty-one".