81503397 has 12 divisors (see below), whose sum is σ = 118770444. Its totient is φ = 53854080.

The previous prime is 81503363. The next prime is 81503473. The reversal of 81503397 is 79330518.

It can be written as a sum of positive squares in 2 ways, for example, as 12047841 + 69455556 = 3471^2 + 8334^2 .

It is not a de Polignac number, because 81503397 - 2²⁰ = 80454821 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81503327) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 39054 + ... + 41087.

It is an arithmetic number, because the mean of its divisors is an integer number (9897537).

Almost surely, 2^81503397 is an apocalyptic number.

It is an amenable number.

81503397 is a deficient number, since it is larger than the sum of its proper divisors (37267047).

81503397 is a wasteful number, since it uses less digits than its factorization.

81503397 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80260 (or 80257 counting only the distinct ones).

The product of its (nonzero) digits is 22680, while the sum is 36.

The square root of 81503397 is about 9027.9231831025. The cubic root of 81503397 is about 433.5693467123.

The spelling of 81503397 in words is "eighty-one million, five hundred three thousand, three hundred ninety-seven".