81797026 has 4 divisors (see below), whose sum is σ = 122695542. Its totient is φ = 40898512.

The previous prime is 81797021. The next prime is 81797029. The reversal of 81797026 is 62079718.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 62079718 = 2 ⋅31039859.

It can be written as a sum of positive squares in only one way, i.e., 79834225 + 1962801 = 8935^2 + 1401^2 .

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a self number, because there is not a number n which added to its sum of digits gives 81797026.

It is not an unprimeable number, because it can be changed into a prime (81797021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20449255 + ... + 20449258.

Almost surely, 2^81797026 is an apocalyptic number.

81797026 is a deficient number, since it is larger than the sum of its proper divisors (40898516).

81797026 is a wasteful number, since it uses less digits than its factorization.

81797026 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40898515.

The product of its (nonzero) digits is 42336, while the sum is 40.

The square root of 81797026 is about 9044.1708298771. The cubic root of 81797026 is about 434.0893902955.

The spelling of 81797026 in words is "eighty-one million, seven hundred ninety-seven thousand, twenty-six".