87081989 has 2 divisors, whose sum is σ = 87081990. Its totient is φ = 87081988.

The previous prime is 87081941. The next prime is 87082003. The reversal of 87081989 is 98918078.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 78021889 + 9060100 = 8833^2 + 3010^2 .

It is a cyclic number.

It is not a de Polignac number, because 87081989 - 2⁸ = 87081733 is a prime.

It is a super-2 number, since 2×87081989² = 15166545616392242, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (87083989) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43540994 + 43540995.

It is an arithmetic number, because the mean of its divisors is an integer number (43540995).

Almost surely, 2^87081989 is an apocalyptic number.

It is an amenable number.

87081989 is a deficient number, since it is larger than the sum of its proper divisors (1).

87081989 is an equidigital number, since it uses as much as digits as its factorization.

87081989 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 290304, while the sum is 50.

The square root of 87081989 is about 9331.7730898260. The cubic root of 87081989 is about 443.2439127821.

The spelling of 87081989 in words is "eighty-seven million, eighty-one thousand, nine hundred eighty-nine".