81205396 has 24 divisors (see below), whose sum is σ = 152943336. Its totient is φ = 37585920.

The previous prime is 81205367. The next prime is 81205409. The reversal of 81205396 is 69350218.

It can be written as a sum of positive squares in 4 ways, for example, as 19802500 + 61402896 = 4450^2 + 7836^2 .

It is a Harshad number since it is a multiple of its sum of digits (34).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5641 + ... + 13936.

It is an arithmetic number, because the mean of its divisors is an integer number (6372639).

Almost surely, 2^81205396 is an apocalyptic number.

It is an amenable number.

81205396 is a deficient number, since it is larger than the sum of its proper divisors (71737940).

81205396 is a wasteful number, since it uses less digits than its factorization.

81205396 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19659 (or 19657 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 34.

The square root of 81205396 is about 9011.4036642468. The cubic root of 81205396 is about 433.0402812826.

The spelling of 81205396 in words is "eighty-one million, two hundred five thousand, three hundred ninety-six".