81490989600 has 720 divisors, whose sum is σ = 310345136640. Its totient is φ = 20785766400.

The previous prime is 81490989583. The next prime is 81490989611. The reversal of 81490989600 is 698909418.

81490989600 is a `hidden beast` number, since 8 + 1 + 490 + 98 + 9 + 60 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (720).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 226994221 + ... + 226994579.

It is an arithmetic number, because the mean of its divisors is an integer number (431034912).

Almost surely, 2^81490989600 is an apocalyptic number.

81490989600 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 81490989600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (155172568320).

81490989600 is an abundant number, since it is smaller than the sum of its proper divisors (228854147040).

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

81490989600 is a wasteful number, since it uses less digits than its factorization.

81490989600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 535 (or 513 counting only the distinct ones).

The product of its (nonzero) digits is 1119744, while the sum is 54.

The spelling of 81490989600 in words is "eighty-one billion, four hundred ninety million, nine hundred eighty-nine thousand, six hundred".