81770786 has 8 divisors (see below), whose sum is σ = 122704284. Its totient is φ = 40869360.

The previous prime is 81770723. The next prime is 81770789. The reversal of 81770786 is 68707718.

It can be written as a sum of positive squares in 2 ways, for example, as 70040161 + 11730625 = 8369^2 + 3425^2 .

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

It is a super-2 number, since 2×81770786² = 13372922886115592, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81770789) 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, 65 + ... + 12788.

Almost surely, 2^81770786 is an apocalyptic number.

81770786 is a deficient number, since it is larger than the sum of its proper divisors (40933498).

81770786 is a wasteful number, since it uses less digits than its factorization.

81770786 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16036.

The product of its (nonzero) digits is 131712, while the sum is 44.

The square root of 81770786 is about 9042.7200553816. The cubic root of 81770786 is about 434.0429675652.

The spelling of 81770786 in words is "eighty-one million, seven hundred seventy thousand, seven hundred eighty-six".