81549037 has 2 divisors, whose sum is σ = 81549038. Its totient is φ = 81549036.

The previous prime is 81549031. The next prime is 81549043. The reversal of 81549037 is 73094518.

It is a balanced prime because it is at equal distance from previous prime (81549031) and next prime (81549043).

It can be written as a sum of positive squares in only one way, i.e., 46158436 + 35390601 = 6794^2 + 5949^2 .

It is a cyclic number.

It is not a de Polignac number, because 81549037 - 2³ = 81549029 is a prime.

It is a super-3 number, since 3×81549037³ (a number of 25 digits) contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81548987 and 81549005.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81549031) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40774518 + 40774519.

It is an arithmetic number, because the mean of its divisors is an integer number (40774519).

Almost surely, 2^81549037 is an apocalyptic number.

It is an amenable number.

81549037 is a deficient number, since it is larger than the sum of its proper divisors (1).

81549037 is an equidigital number, since it uses as much as digits as its factorization.

81549037 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 30240, while the sum is 37.

The square root of 81549037 is about 9030.4505424702. The cubic root of 81549037 is about 433.6502611823.

The spelling of 81549037 in words is "eighty-one million, five hundred forty-nine thousand, thirty-seven".