81307648 has 72 divisors (see below), whose sum is σ = 172849950. Its totient is φ = 38191104.

The previous prime is 81307609. The next prime is 81307657. The reversal of 81307648 is 84670318.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 80856064 + 451584 = 8992^2 + 672^2 .

It is a super-2 number, since 2×81307648² = 13221867246583808, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2197486 + ... + 2197522.

Almost surely, 2^81307648 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 81307648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (86424975).

81307648 is an abundant number, since it is smaller than the sum of its proper divisors (91542302).

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

81307648 is an equidigital number, since it uses as much as digits as its factorization.

81307648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 125 (or 68 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 37.

The square root of 81307648 is about 9017.0753573429. The cubic root of 81307648 is about 433.2219632269.

The spelling of 81307648 in words is "eighty-one million, three hundred seven thousand, six hundred forty-eight".