81401783 has 2 divisors, whose sum is σ = 81401784. Its totient is φ = 81401782.

The previous prime is 81401777. The next prime is 81401809. The reversal of 81401783 is 38710418.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81401783 - 2¹⁶ = 81336247 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81401183) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40700891 + 40700892.

It is an arithmetic number, because the mean of its divisors is an integer number (40700892).

Almost surely, 2^81401783 is an apocalyptic number.

81401783 is a deficient number, since it is larger than the sum of its proper divisors (1).

81401783 is an equidigital number, since it uses as much as digits as its factorization.

81401783 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5376, while the sum is 32.

The square root of 81401783 is about 9022.2936662470. The cubic root of 81401783 is about 433.3890882237.

The spelling of 81401783 in words is "eighty-one million, four hundred one thousand, seven hundred eighty-three".