81370697 has 4 divisors (see below), whose sum is σ = 81388740. Its totient is φ = 81352656.

The previous prime is 81370651. The next prime is 81370699. The reversal of 81370697 is 79607318.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 14523721 + 66846976 = 3811^2 + 8176^2 .

It is a cyclic number.

It is not a de Polignac number, because 81370697 - 2⁶ = 81370633 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81370699) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4379 + ... + 13487.

It is an arithmetic number, because the mean of its divisors is an integer number (20347185).

Almost surely, 2^81370697 is an apocalyptic number.

It is an amenable number.

81370697 is a deficient number, since it is larger than the sum of its proper divisors (18043).

81370697 is an equidigital number, since it uses as much as digits as its factorization.

81370697 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18042.

The product of its (nonzero) digits is 63504, while the sum is 41.

The square root of 81370697 is about 9020.5707690811. The cubic root of 81370697 is about 433.3339131485. Note that the first 3 decimals are identical.

The spelling of 81370697 in words is "eighty-one million, three hundred seventy thousand, six hundred ninety-seven".