81207766 has 8 divisors (see below), whose sum is σ = 124110144. Its totient is φ = 39837720.

The previous prime is 81207761. The next prime is 81207769. The reversal of 81207766 is 66770218.

It is a happy number.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81207761) 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, 382950 + ... + 383161.

It is an arithmetic number, because the mean of its divisors is an integer number (15513768).

Almost surely, 2^81207766 is an apocalyptic number.

81207766 is a deficient number, since it is larger than the sum of its proper divisors (42902378).

81207766 is a wasteful number, since it uses less digits than its factorization.

81207766 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 766166.

The product of its (nonzero) digits is 28224, while the sum is 37.

The square root of 81207766 is about 9011.5351633337. The cubic root of 81207766 is about 433.0444940383.

The spelling of 81207766 in words is "eighty-one million, two hundred seven thousand, seven hundred sixty-six".