81207504 has 180 divisors, whose sum is σ = 280338084. Its totient is φ = 21805056.

The previous prime is 81207491. The next prime is 81207517. The reversal of 81207504 is 40570218.

It is an interprime number because it is at equal distance from previous prime (81207491) and next prime (81207517).

It can be written as a sum of positive squares in 2 ways, for example, as 74857104 + 6350400 = 8652^2 + 2520^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 119614 + ... + 120290.

Almost surely, 2^81207504 is an apocalyptic number.

81207504 is a gapful number since it is divisible by the number (84) 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 81207504, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (140169042).

81207504 is an abundant number, since it is smaller than the sum of its proper divisors (199130580).

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

81207504 is a wasteful number, since it uses less digits than its factorization.

81207504 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 722 (or 706 counting only the distinct ones).

The product of its (nonzero) digits is 2240, while the sum is 27.

The square root of 81207504 is about 9011.5206263982. The cubic root of 81207504 is about 433.0440283284.

The spelling of 81207504 in words is "eighty-one million, two hundred seven thousand, five hundred four".