81964558 has 16 divisors (see below), whose sum is σ = 136676736. Its totient is φ = 36609120.

The previous prime is 81964543. The next prime is 81964559. The reversal of 81964558 is 85546918.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81964559) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 50041 + ... + 51652.

It is an arithmetic number, because the mean of its divisors is an integer number (8542296).

Almost surely, 2^81964558 is an apocalyptic number.

81964558 is a deficient number, since it is larger than the sum of its proper divisors (54712178).

81964558 is a wasteful number, since it uses less digits than its factorization.

81964558 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 101739.

The product of its digits is 345600, while the sum is 46.

The square root of 81964558 is about 9053.4279695594. The cubic root of 81964558 is about 434.3855472345.

The spelling of 81964558 in words is "eighty-one million, nine hundred sixty-four thousand, five hundred fifty-eight".