87787561 has 2 divisors, whose sum is σ = 87787562. Its totient is φ = 87787560.

The previous prime is 87787547. The next prime is 87787591. The reversal of 87787561 is 16578778.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 80192025 + 7595536 = 8955^2 + 2756^2 .

It is a cyclic number.

It is not a de Polignac number, because 87787561 - 2⁷ = 87787433 is a prime.

It is not a weakly prime, because it can be changed into another prime (87787591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43893780 + 43893781.

It is an arithmetic number, because the mean of its divisors is an integer number (43893781).

Almost surely, 2^87787561 is an apocalyptic number.

It is an amenable number.

87787561 is a deficient number, since it is larger than the sum of its proper divisors (1).

87787561 is an equidigital number, since it uses as much as digits as its factorization.

87787561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 658560, while the sum is 49.

The square root of 87787561 is about 9369.5016409626. The cubic root of 87787561 is about 444.4378053846.

The spelling of 87787561 in words is "eighty-seven million, seven hundred eighty-seven thousand, five hundred sixty-one".