81644962418 has 16 divisors (see below), whose sum is σ = 124046457696. Its totient is φ = 40296964800.

The previous prime is 81644962411. The next prime is 81644962493. The reversal of 81644962418 is 81426944618.

It is a self number, because there is not a number n which added to its sum of digits gives 81644962418.

It is not an unprimeable number, because it can be changed into a prime (81644962411) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5396 + ... + 404127.

It is an arithmetic number, because the mean of its divisors is an integer number (7752903606).

Almost surely, 2^81644962418 is an apocalyptic number.

81644962418 is a deficient number, since it is larger than the sum of its proper divisors (42401495278).

81644962418 is a wasteful number, since it uses less digits than its factorization.

81644962418 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 410809.

The product of its digits is 2654208, while the sum is 53.

The spelling of 81644962418 in words is "eighty-one billion, six hundred forty-four million, nine hundred sixty-two thousand, four hundred eighteen".