81948641 has 2 divisors, whose sum is σ = 81948642. Its totient is φ = 81948640.

The previous prime is 81948631. The next prime is 81948677. The reversal of 81948641 is 14684918.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 45900625 + 36048016 = 6775^2 + 6004^2 .

It is a cyclic number.

It is not a de Polignac number, because 81948641 - 2²² = 77754337 is a prime.

It is a Chen prime.

It is equal to p_4776584 and since 81948641 and 4776584 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (81948631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40974320 + 40974321.

It is an arithmetic number, because the mean of its divisors is an integer number (40974321).

Almost surely, 2^81948641 is an apocalyptic number.

It is an amenable number.

81948641 is a deficient number, since it is larger than the sum of its proper divisors (1).

81948641 is an equidigital number, since it uses as much as digits as its factorization.

81948641 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 55296, while the sum is 41.

The square root of 81948641 is about 9052.5488675842. The cubic root of 81948641 is about 434.3574271034.

The spelling of 81948641 in words is "eighty-one million, nine hundred forty-eight thousand, six hundred forty-one".