81003766 has 4 divisors (see below), whose sum is σ = 121505652. Its totient is φ = 40501882.

The previous prime is 81003763. The next prime is 81003781. The reversal of 81003766 is 66730018.

It is a semiprime because it is the product of two primes.

It is a super-2 number, since 2×81003766² = 13123220212365512, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81003761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20250940 + ... + 20250943.

It is an arithmetic number, because the mean of its divisors is an integer number (30376413).

Almost surely, 2^81003766 is an apocalyptic number.

81003766 is a deficient number, since it is larger than the sum of its proper divisors (40501886).

81003766 is a wasteful number, since it uses less digits than its factorization.

81003766 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40501885.

The product of its (nonzero) digits is 6048, while the sum is 31.

The square root of 81003766 is about 9000.2092197904. The cubic root of 81003766 is about 432.6815765585.

The spelling of 81003766 in words is "eighty-one million, three thousand, seven hundred sixty-six".