81778422 has 16 divisors (see below), whose sum is σ = 178425792. Its totient is φ = 24781320.

The previous prime is 81778379. The next prime is 81778423. The reversal of 81778422 is 22487718.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81778423) 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, 619468 + ... + 619599.

It is an arithmetic number, because the mean of its divisors is an integer number (11151612).

Almost surely, 2^81778422 is an apocalyptic number.

81778422 is an abundant number, since it is smaller than the sum of its proper divisors (96647370).

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

81778422 is a wasteful number, since it uses less digits than its factorization.

81778422 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1239083.

The product of its digits is 50176, while the sum is 39.

The square root of 81778422 is about 9043.1422636161. The cubic root of 81778422 is about 434.0564778872.

The spelling of 81778422 in words is "eighty-one million, seven hundred seventy-eight thousand, four hundred twenty-two".