81405967804 has 48 divisors (see below), whose sum is σ = 167431337920. Its totient is φ = 33900871680.

The previous prime is 81405967777. The next prime is 81405967807. The reversal of 81405967804 is 40876950418.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81405967807) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 745594 + ... + 847774.

Almost surely, 2^81405967804 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81405967804, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (83715668960).

81405967804 is an abundant number, since it is smaller than the sum of its proper divisors (86025370116).

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

81405967804 is a wasteful number, since it uses less digits than its factorization.

81405967804 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 102998 (or 102996 counting only the distinct ones).

The product of its (nonzero) digits is 1935360, while the sum is 52.

The spelling of 81405967804 in words is "eighty-one billion, four hundred five million, nine hundred sixty-seven thousand, eight hundred four".