81307497 has 8 divisors (see below), whose sum is σ = 109075744. Its totient is φ = 53872128.

The previous prime is 81307477. The next prime is 81307519. The reversal of 81307497 is 79470318.

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

It is not a de Polignac number, because 81307497 - 2¹⁶ = 81241961 is a prime.

It is a super-2 number, since 2×81307497² = 13221818136810018, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81307417) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 82648 + ... + 83625.

It is an arithmetic number, because the mean of its divisors is an integer number (13634468).

Almost surely, 2^81307497 is an apocalyptic number.

It is an amenable number.

81307497 is a deficient number, since it is larger than the sum of its proper divisors (27768247).

81307497 is a wasteful number, since it uses less digits than its factorization.

81307497 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 166439.

The product of its (nonzero) digits is 42336, while the sum is 39.

The square root of 81307497 is about 9017.0669843359. The cubic root of 81307497 is about 433.2216950416.

The spelling of 81307497 in words is "eighty-one million, three hundred seven thousand, four hundred ninety-seven".