81224387 has 2 divisors, whose sum is σ = 81224388. Its totient is φ = 81224386.

The previous prime is 81224383. The next prime is 81224417. The reversal of 81224387 is 78342218.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81224387 - 2² = 81224383 is a prime.

It is not a weakly prime, because it can be changed into another prime (81224383) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40612193 + 40612194.

It is an arithmetic number, because the mean of its divisors is an integer number (40612194).

Almost surely, 2^81224387 is an apocalyptic number.

81224387 is a deficient number, since it is larger than the sum of its proper divisors (1).

81224387 is an equidigital number, since it uses as much as digits as its factorization.

81224387 is an evil number, because the sum of its binary digits is even.

The product of its digits is 21504, while the sum is 35.

The square root of 81224387 is about 9012.4573230612. The cubic root of 81224387 is about 433.0740361289.

The spelling of 81224387 in words is "eighty-one million, two hundred twenty-four thousand, three hundred eighty-seven".