81767420 has 24 divisors (see below), whose sum is σ = 196242144. Its totient is φ = 28034496.

The previous prime is 81767419. The next prime is 81767423. The reversal of 81767420 is 2476718.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81767423) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 291887 + ... + 292166.

It is an arithmetic number, because the mean of its divisors is an integer number (8176756).

Almost surely, 2^81767420 is an apocalyptic number.

It is an amenable number.

81767420 is an abundant number, since it is smaller than the sum of its proper divisors (114474724).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81767420 is a wasteful number, since it uses less digits than its factorization.

81767420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 584069 (or 584067 counting only the distinct ones).

The product of its (nonzero) digits is 18816, while the sum is 35.

The square root of 81767420 is about 9042.5339369007. The cubic root of 81767420 is about 434.0370118576.

The spelling of 81767420 in words is "eighty-one million, seven hundred sixty-seven thousand, four hundred twenty".