81631525248 has 640 divisors, whose sum is σ = 308751421440. Its totient is φ = 20827238400.

The previous prime is 81631525247. The next prime is 81631525271. The reversal of 81631525248 is 84252513618.

81631525248 is a `hidden beast` number, since 8 + 1 + 631 + 5 + 2 + 5 + 2 + 4 + 8 = 666.

It is a super-2 number, since 2×81631525248² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81631525247) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 29246733 + ... + 29249523.

It is an arithmetic number, because the mean of its divisors is an integer number (482424096).

Almost surely, 2^81631525248 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 81631525248, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (154375710720).

81631525248 is an abundant number, since it is smaller than the sum of its proper divisors (227119896192).

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

81631525248 is a wasteful number, since it uses less digits than its factorization.

81631525248 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2868 (or 2847 counting only the distinct ones).

The product of its digits is 460800, while the sum is 45.

The spelling of 81631525248 in words is "eighty-one billion, six hundred thirty-one million, five hundred twenty-five thousand, two hundred forty-eight".