81849397 has 16 divisors (see below), whose sum is σ = 101865600. Its totient is φ = 64169280.

The previous prime is 81849389. The next prime is 81849401. The reversal of 81849397 is 79394818.

It is a happy number.

It is not a de Polignac number, because 81849397 - 2³ = 81849389 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81849397.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81849347) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6754 + ... + 14467.

It is an arithmetic number, because the mean of its divisors is an integer number (6366600).

Almost surely, 2^81849397 is an apocalyptic number.

It is an amenable number.

81849397 is a deficient number, since it is larger than the sum of its proper divisors (20016203).

81849397 is a wasteful number, since it uses less digits than its factorization.

81849397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21276.

The product of its digits is 435456, while the sum is 49.

The square root of 81849397 is about 9047.0656568857. The cubic root of 81849397 is about 434.1820132449.

The spelling of 81849397 in words is "eighty-one million, eight hundred forty-nine thousand, three hundred ninety-seven".