81654649 has 2 divisors, whose sum is σ = 81654650. Its totient is φ = 81654648.

The previous prime is 81654631. The next prime is 81654667. The reversal of 81654649 is 94645618.

It is a balanced prime because it is at equal distance from previous prime (81654631) and next prime (81654667).

It can be written as a sum of positive squares in only one way, i.e., 49449024 + 32205625 = 7032^2 + 5675^2 .

It is a cyclic number.

It is not a de Polignac number, because 81654649 - 2¹⁷ = 81523577 is a prime.

It is not a weakly prime, because it can be changed into another prime (81654619) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40827324 + 40827325.

It is an arithmetic number, because the mean of its divisors is an integer number (40827325).

Almost surely, 2^81654649 is an apocalyptic number.

It is an amenable number.

81654649 is a deficient number, since it is larger than the sum of its proper divisors (1).

81654649 is an equidigital number, since it uses as much as digits as its factorization.

81654649 is an evil number, because the sum of its binary digits is even.

The product of its digits is 207360, while the sum is 43.

The square root of 81654649 is about 9036.2961992179. The cubic root of 81654649 is about 433.8373834194.

The spelling of 81654649 in words is "eighty-one million, six hundred fifty-four thousand, six hundred forty-nine".