81680770 has 16 divisors (see below), whose sum is σ = 148101048. Its totient is φ = 32433280.

The previous prime is 81680761. The next prime is 81680771. The reversal of 81680770 is 7708618.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 77316849 + 4363921 = 8793^2 + 2089^2 .

It is not an unprimeable number, because it can be changed into a prime (81680771) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28441 + ... + 31180.

Almost surely, 2^81680770 is an apocalyptic number.

81680770 is a deficient number, since it is larger than the sum of its proper divisors (66420278).

81680770 is a wasteful number, since it uses less digits than its factorization.

81680770 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59765.

The product of its (nonzero) digits is 18816, while the sum is 37.

The square root of 81680770 is about 9037.7414213951. The cubic root of 81680770 is about 433.8836394430.

The spelling of 81680770 in words is "eighty-one million, six hundred eighty thousand, seven hundred seventy".