81402019 has 2 divisors, whose sum is σ = 81402020. Its totient is φ = 81402018.

The previous prime is 81402017. The next prime is 81402031. The reversal of 81402019 is 91020418.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81402019 - 2¹ = 81402017 is a prime.

It is a super-2 number, since 2×81402019² = 13252577394552722, which contains 22 as substring.

Together with 81402017, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 81401984 and 81402002.

It is not a weakly prime, because it can be changed into another prime (81402017) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40701009 + 40701010.

It is an arithmetic number, because the mean of its divisors is an integer number (40701010).

Almost surely, 2^81402019 is an apocalyptic number.

81402019 is a deficient number, since it is larger than the sum of its proper divisors (1).

81402019 is an equidigital number, since it uses as much as digits as its factorization.

81402019 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 81402019 is about 9022.3067449516. The cubic root of 81402019 is about 433.3895070505.

The spelling of 81402019 in words is "eighty-one million, four hundred two thousand, nineteen".