81229987 has 2 divisors, whose sum is σ = 81229988. Its totient is φ = 81229986.

The previous prime is 81229963. The next prime is 81229991. The reversal of 81229987 is 78992218.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81229987 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (81229787) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40614993 + 40614994.

It is an arithmetic number, because the mean of its divisors is an integer number (40614994).

Almost surely, 2^81229987 is an apocalyptic number.

81229987 is a deficient number, since it is larger than the sum of its proper divisors (1).

81229987 is an equidigital number, since it uses as much as digits as its factorization.

81229987 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 145152, while the sum is 46.

The square root of 81229987 is about 9012.7679987893. The cubic root of 81229987 is about 433.0839886360.

The spelling of 81229987 in words is "eighty-one million, two hundred twenty-nine thousand, nine hundred eighty-seven".