81379783 has 2 divisors, whose sum is σ = 81379784. Its totient is φ = 81379782.

The previous prime is 81379769. The next prime is 81379807. The reversal of 81379783 is 38797318.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81379783 - 2¹⁷ = 81248711 is a prime.

It is a super-2 number, since 2×81379783² = 13245338162254178, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81379723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40689891 + 40689892.

It is an arithmetic number, because the mean of its divisors is an integer number (40689892).

Almost surely, 2^81379783 is an apocalyptic number.

81379783 is a deficient number, since it is larger than the sum of its proper divisors (1).

81379783 is an equidigital number, since it uses as much as digits as its factorization.

81379783 is an evil number, because the sum of its binary digits is even.

The product of its digits is 254016, while the sum is 46.

The square root of 81379783 is about 9021.0743816909. The cubic root of 81379783 is about 433.3500414991.

The spelling of 81379783 in words is "eighty-one million, three hundred seventy-nine thousand, seven hundred eighty-three".