81511449600 has 1056 divisors, whose sum is σ = 326979198976. Its totient is φ = 17517772800.

The previous prime is 81511449563. The next prime is 81511449689. The reversal of 81511449600 is 694411518.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1116595164 + ... + 1116595236.

Almost surely, 2^81511449600 is an apocalyptic number.

81511449600 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 81511449600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (163489599488).

81511449600 is an abundant number, since it is smaller than the sum of its proper divisors (245467749376).

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

81511449600 is a wasteful number, since it uses less digits than its factorization.

81511449600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 211 (or 188 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 39.

The spelling of 81511449600 in words is "eighty-one billion, five hundred eleven million, four hundred forty-nine thousand, six hundred".