81948749 has 2 divisors, whose sum is σ = 81948750. Its totient is φ = 81948748.

The previous prime is 81948733. The next prime is 81948781. The reversal of 81948749 is 94784918.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 79530724 + 2418025 = 8918^2 + 1555^2 .

It is a cyclic number.

It is not a de Polignac number, because 81948749 - 2⁴ = 81948733 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 81948697 and 81948706.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81948949) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40974374 + 40974375.

It is an arithmetic number, because the mean of its divisors is an integer number (40974375).

Almost surely, 2^81948749 is an apocalyptic number.

It is an amenable number.

81948749 is a deficient number, since it is larger than the sum of its proper divisors (1).

81948749 is an equidigital number, since it uses as much as digits as its factorization.

81948749 is an evil number, because the sum of its binary digits is even.

The product of its digits is 580608, while the sum is 50.

The square root of 81948749 is about 9052.5548327530. The cubic root of 81948749 is about 434.3576179163.

The spelling of 81948749 in words is "eighty-one million, nine hundred forty-eight thousand, seven hundred forty-nine".