81698406400 has 360 divisors, whose sum is σ = 222414531920. Its totient is φ = 29585571840.

The previous prime is 81698406359. The next prime is 81698406401. The reversal of 81698406400 is 460489618.

It is not an unprimeable number, because it can be changed into a prime (81698406401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 356761486 + ... + 356761714.

Almost surely, 2^81698406400 is an apocalyptic number.

81698406400 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81698406400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (111207265960).

81698406400 is an abundant number, since it is smaller than the sum of its proper divisors (140716125520).

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

81698406400 is a wasteful number, since it uses less digits than its factorization.

81698406400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 347 (or 316 counting only the distinct ones).

The product of its (nonzero) digits is 331776, while the sum is 46.

The spelling of 81698406400 in words is "eighty-one billion, six hundred ninety-eight million, four hundred six thousand, four hundred".