81982157 has 2 divisors, whose sum is σ = 81982158. Its totient is φ = 81982156.

The previous prime is 81982127. The next prime is 81982193. The reversal of 81982157 is 75128918.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 53743561 + 28238596 = 7331^2 + 5314^2 .

It is a cyclic number.

It is not a de Polignac number, because 81982157 - 2⁸ = 81981901 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81982127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40991078 + 40991079.

It is an arithmetic number, because the mean of its divisors is an integer number (40991079).

Almost surely, 2^81982157 is an apocalyptic number.

It is an amenable number.

81982157 is a deficient number, since it is larger than the sum of its proper divisors (1).

81982157 is an equidigital number, since it uses as much as digits as its factorization.

81982157 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 40320, while the sum is 41.

The square root of 81982157 is about 9054.3998696766. The cubic root of 81982157 is about 434.4166346718.

The spelling of 81982157 in words is "eighty-one million, nine hundred eighty-two thousand, one hundred fifty-seven".