81394790400 has 1872 divisors, whose sum is σ = 385342384128. Its totient is φ = 15925248000.

The previous prime is 81394790381. The next prime is 81394790443. The reversal of 81394790400 is 409749318.

81394790400 is a `hidden beast` number, since 8 + 139 + 479 + 0 + 40 + 0 = 666.

It is a super-2 number, since 2×81394790400² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 2199859182 + ... + 2199859218.

Almost surely, 2^81394790400 is an apocalyptic number.

81394790400 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 81394790400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (192671192064).

81394790400 is an abundant number, since it is smaller than the sum of its proper divisors (303947593728).

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

81394790400 is a wasteful number, since it uses less digits than its factorization.

81394790400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 126 (or 96 counting only the distinct ones).

The product of its (nonzero) digits is 217728, while the sum is 45.

The spelling of 81394790400 in words is "eighty-one billion, three hundred ninety-four million, seven hundred ninety thousand, four hundred".