81290336 has 12 divisors (see below), whose sum is σ = 160040412. Its totient is φ = 40645152.

The previous prime is 81290329. The next prime is 81290351. The reversal of 81290336 is 63309218.

It is a Harshad number since it is a multiple of its sum of digits (32), and also a Moran number because the ratio is a prime number: 2540323 = 81290336 / (8 + 1 + 2 + 9 + 0 + 3 + 3 + 6).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1270130 + ... + 1270193.

It is an arithmetic number, because the mean of its divisors is an integer number (13336701).

Almost surely, 2^81290336 is an apocalyptic number.

It is an amenable number.

81290336 is a deficient number, since it is larger than the sum of its proper divisors (78750076).

81290336 is a wasteful number, since it uses less digits than its factorization.

81290336 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2540333 (or 2540325 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 32.

The square root of 81290336 is about 9016.1153497501. The cubic root of 81290336 is about 433.1912138810.

The spelling of 81290336 in words is "eighty-one million, two hundred ninety thousand, three hundred thirty-six".