81952139 has 2 divisors, whose sum is σ = 81952140. Its totient is φ = 81952138.

The previous prime is 81952069. The next prime is 81952147. The reversal of 81952139 is 93125918.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81952139 is a prime.

It is a super-3 number, since 3×81952139³ (a number of 25 digits) contains 333 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (81952639) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40976069 + 40976070.

It is an arithmetic number, because the mean of its divisors is an integer number (40976070).

Almost surely, 2^81952139 is an apocalyptic number.

81952139 is a deficient number, since it is larger than the sum of its proper divisors (1).

81952139 is an equidigital number, since it uses as much as digits as its factorization.

81952139 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 19440, while the sum is 38.

The square root of 81952139 is about 9052.7420707761. The cubic root of 81952139 is about 434.3636072370.

The spelling of 81952139 in words is "eighty-one million, nine hundred fifty-two thousand, one hundred thirty-nine".