87881581 has 2 divisors, whose sum is σ = 87881582. Its totient is φ = 87881580.

The previous prime is 87881543. The next prime is 87881603. The reversal of 87881581 is 18518878.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 87796900 + 84681 = 9370^2 + 291^2 .

It is a cyclic number.

It is not a de Polignac number, because 87881581 - 2⁹ = 87881069 is a prime.

It is a super-2 number, since 2×87881581² = 15446344558119122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (87881501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43940790 + 43940791.

It is an arithmetic number, because the mean of its divisors is an integer number (43940791).

Almost surely, 2^87881581 is an apocalyptic number.

It is an amenable number.

87881581 is a deficient number, since it is larger than the sum of its proper divisors (1).

87881581 is an equidigital number, since it uses as much as digits as its factorization.

87881581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 143360, while the sum is 46.

The square root of 87881581 is about 9374.5176409243. The cubic root of 87881581 is about 444.5964122659.

The spelling of 87881581 in words is "eighty-seven million, eight hundred eighty-one thousand, five hundred eighty-one".