81773956 has 24 divisors (see below), whose sum is σ = 156671424. Its totient is φ = 37037280.

The previous prime is 81773953. The next prime is 81773957. The reversal of 81773956 is 65937718.

It is not an unprimeable number, because it can be changed into a prime (81773953) 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, 9721 + ... + 16063.

It is an arithmetic number, because the mean of its divisors is an integer number (6527976).

Almost surely, 2^81773956 is an apocalyptic number.

It is an amenable number.

81773956 is a deficient number, since it is larger than the sum of its proper divisors (74897468).

81773956 is a wasteful number, since it uses less digits than its factorization.

81773956 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6651 (or 6649 counting only the distinct ones).

The product of its digits is 317520, while the sum is 46.

The square root of 81773956 is about 9042.8953328013. The cubic root of 81773956 is about 434.0485763264.

The spelling of 81773956 in words is "eighty-one million, seven hundred seventy-three thousand, nine hundred fifty-six".