81471739 has 2 divisors, whose sum is σ = 81471740. Its totient is φ = 81471738.

The previous prime is 81471707. The next prime is 81471749. The reversal of 81471739 is 93717418.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81471739 - 2⁵ = 81471707 is a prime.

It is not a weakly prime, because it can be changed into another prime (81471749) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40735869 + 40735870.

It is an arithmetic number, because the mean of its divisors is an integer number (40735870).

Almost surely, 2^81471739 is an apocalyptic number.

81471739 is a deficient number, since it is larger than the sum of its proper divisors (1).

81471739 is an equidigital number, since it uses as much as digits as its factorization.

81471739 is an evil number, because the sum of its binary digits is even.

The product of its digits is 42336, while the sum is 40.

The square root of 81471739 is about 9026.1696748953. The cubic root of 81471739 is about 433.5132029750.

The spelling of 81471739 in words is "eighty-one million, four hundred seventy-one thousand, seven hundred thirty-nine".