81490919 has 2 divisors, whose sum is σ = 81490920. Its totient is φ = 81490918.

The previous prime is 81490901. The next prime is 81490973. The reversal of 81490919 is 91909418.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81490919 - 2²⁰ = 80442343 is a prime.

It is a super-2 number, since 2×81490919² = 13281539758929122, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81498919) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40745459 + 40745460.

It is an arithmetic number, because the mean of its divisors is an integer number (40745460).

Almost surely, 2^81490919 is an apocalyptic number.

81490919 is a deficient number, since it is larger than the sum of its proper divisors (1).

81490919 is an equidigital number, since it uses as much as digits as its factorization.

81490919 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 23328, while the sum is 41.

The square root of 81490919 is about 9027.2320785499. The cubic root of 81490919 is about 433.5472193956.

The spelling of 81490919 in words is "eighty-one million, four hundred ninety thousand, nine hundred nineteen".