81965776 has 20 divisors (see below), whose sum is σ = 160448932. Its totient is φ = 40559616.

The previous prime is 81965759. The next prime is 81965777. The reversal of 81965776 is 67756918.

It can be written as a sum of positive squares in 2 ways, for example, as 10732176 + 71233600 = 3276^2 + 8440^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81965777) 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, 24855 + ... + 27958.

Almost surely, 2^81965776 is an apocalyptic number.

It is an amenable number.

81965776 is a deficient number, since it is larger than the sum of its proper divisors (78483156).

81965776 is a wasteful number, since it uses less digits than its factorization.

81965776 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52918 (or 52912 counting only the distinct ones).

The product of its digits is 635040, while the sum is 49.

The square root of 81965776 is about 9053.4952366476. The cubic root of 81965776 is about 434.3876988921.

The spelling of 81965776 in words is "eighty-one million, nine hundred sixty-five thousand, seven hundred seventy-six".