81549725422 has 16 divisors (see below), whose sum is σ = 135324514944. Its totient is φ = 36545971000.

The previous prime is 81549725417. The next prime is 81549725423. The reversal of 81549725422 is 22452794518.

It is a super-4 number, since 4×81549725422⁴ (a number of 45 digits) contains 4444 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81549725423) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 26102704 + ... + 26105827.

It is an arithmetic number, because the mean of its divisors is an integer number (8457782184).

Almost surely, 2^81549725422 is an apocalyptic number.

81549725422 is a deficient number, since it is larger than the sum of its proper divisors (53774789522).

81549725422 is a wasteful number, since it uses less digits than its factorization.

81549725422 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52208615.

The product of its digits is 1612800, while the sum is 49.

The spelling of 81549725422 in words is "eighty-one billion, five hundred forty-nine million, seven hundred twenty-five thousand, four hundred twenty-two".