81222019 has 2 divisors, whose sum is σ = 81222020. Its totient is φ = 81222018.

The previous prime is 81222013. The next prime is 81222059. The reversal of 81222019 is 91022218.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81222019 - 2⁹ = 81221507 is a prime.

It is a super-2 number, since 2×81222019² = 13194032740872722, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81221984 and 81222002.

It is not a weakly prime, because it can be changed into another prime (81222013) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40611009 + 40611010.

It is an arithmetic number, because the mean of its divisors is an integer number (40611010).

Almost surely, 2^81222019 is an apocalyptic number.

81222019 is a deficient number, since it is larger than the sum of its proper divisors (1).

81222019 is an equidigital number, since it uses as much as digits as its factorization.

81222019 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 576, while the sum is 25.

The square root of 81222019 is about 9012.3259483887. The cubic root of 81222019 is about 433.0698275026.

The spelling of 81222019 in words is "eighty-one million, two hundred twenty-two thousand, nineteen".