81503730 has 192 divisors, whose sum is σ = 278553600. Its totient is φ = 16018560.

The previous prime is 81503713. The next prime is 81503731. The reversal of 81503730 is 3730518.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 81503694 and 81503703.

It is not an unprimeable number, because it can be changed into a prime (81503731) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 131361 + ... + 131979.

It is an arithmetic number, because the mean of its divisors is an integer number (1450800).

Almost surely, 2^81503730 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81503730, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (139276800).

81503730 is an abundant number, since it is smaller than the sum of its proper divisors (197049870).

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

81503730 is a wasteful number, since it uses less digits than its factorization.

81503730 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 669 (or 666 counting only the distinct ones).

The product of its (nonzero) digits is 2520, while the sum is 27.

The square root of 81503730 is about 9027.9416258636. The cubic root of 81503730 is about 433.5699371924.

The spelling of 81503730 in words is "eighty-one million, five hundred three thousand, seven hundred thirty".