81538049 has 2 divisors, whose sum is σ = 81538050. Its totient is φ = 81538048.

The previous prime is 81538043. The next prime is 81538073. The reversal of 81538049 is 94083518.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 80425024 + 1113025 = 8968^2 + 1055^2 .

It is a cyclic number.

It is not a de Polignac number, because 81538049 - 2²⁰ = 80489473 is a prime.

It is not a weakly prime, because it can be changed into another prime (81538043) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40769024 + 40769025.

It is an arithmetic number, because the mean of its divisors is an integer number (40769025).

Almost surely, 2^81538049 is an apocalyptic number.

It is an amenable number.

81538049 is a deficient number, since it is larger than the sum of its proper divisors (1).

81538049 is an equidigital number, since it uses as much as digits as its factorization.

81538049 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 34560, while the sum is 38.

The square root of 81538049 is about 9029.8421359401. The cubic root of 81538049 is about 433.6307834820.

The spelling of 81538049 in words is "eighty-one million, five hundred thirty-eight thousand, forty-nine".