81777746 has 16 divisors (see below), whose sum is σ = 124369344. Its totient is φ = 40324944.

The previous prime is 81777743. The next prime is 81777749. The reversal of 81777746 is 64777718.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (81777743) and next prime (81777749).

It is a self number, because there is not a number n which added to its sum of digits gives 81777746.

It is not an unprimeable number, because it can be changed into a prime (81777743) 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, 55556 + ... + 57008.

It is an arithmetic number, because the mean of its divisors is an integer number (7773084).

Almost surely, 2^81777746 is an apocalyptic number.

81777746 is a deficient number, since it is larger than the sum of its proper divisors (42591598).

81777746 is a wasteful number, since it uses less digits than its factorization.

81777746 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1825.

The product of its digits is 460992, while the sum is 47.

The square root of 81777746 is about 9043.1048871502. The cubic root of 81777746 is about 434.0552818790.

The spelling of 81777746 in words is "eighty-one million, seven hundred seventy-seven thousand, seven hundred forty-six".