81390397 has 8 divisors (see below), whose sum is σ = 89576640. Its totient is φ = 73335360.

The previous prime is 81390383. The next prime is 81390473. The reversal of 81390397 is 79309318.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81390397 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81390377) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 31497 + ... + 33982.

It is an arithmetic number, because the mean of its divisors is an integer number (11197080).

Almost surely, 2^81390397 is an apocalyptic number.

It is an amenable number.

81390397 is a deficient number, since it is larger than the sum of its proper divisors (8186243).

81390397 is a wasteful number, since it uses less digits than its factorization.

81390397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65603.

The product of its (nonzero) digits is 40824, while the sum is 40.

The square root of 81390397 is about 9021.6626516402. The cubic root of 81390397 is about 433.3688806473.

The spelling of 81390397 in words is "eighty-one million, three hundred ninety thousand, three hundred ninety-seven".