81763021 has 4 divisors (see below), whose sum is σ = 81781344. Its totient is φ = 81744700.

The previous prime is 81762959. The next prime is 81763037. The reversal of 81763021 is 12036718.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81763021 - 2⁷ = 81762893 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81763621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2376 + ... + 13006.

It is an arithmetic number, because the mean of its divisors is an integer number (20445336).

Almost surely, 2^81763021 is an apocalyptic number.

It is an amenable number.

81763021 is a deficient number, since it is larger than the sum of its proper divisors (18323).

81763021 is a wasteful number, since it uses less digits than its factorization.

81763021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18322.

The product of its (nonzero) digits is 2016, while the sum is 28.

The square root of 81763021 is about 9042.2906942876. The cubic root of 81763021 is about 434.0292281419.

Adding to 81763021 its reverse (12036718), we get a palindrome (93799739).

The spelling of 81763021 in words is "eighty-one million, seven hundred sixty-three thousand, twenty-one".