81207750 has 64 divisors (see below), whose sum is σ = 218312640. Its totient is φ = 19987200.

The previous prime is 81207739. The next prime is 81207761. The reversal of 81207750 is 5770218.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (81207739) and next prime (81207761).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5586 + ... + 13914.

It is an arithmetic number, because the mean of its divisors is an integer number (3411135).

Almost surely, 2^81207750 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81207750, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (109156320).

81207750 is an abundant number, since it is smaller than the sum of its proper divisors (137104890).

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

81207750 is a wasteful number, since it uses less digits than its factorization.

81207750 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8362 (or 8352 counting only the distinct ones).

The product of its (nonzero) digits is 3920, while the sum is 30.

The square root of 81207750 is about 9011.5342755826. The cubic root of 81207750 is about 433.0444655981.

Adding to 81207750 its reverse (5770218), we get a palindrome (86977968).

The spelling of 81207750 in words is "eighty-one million, two hundred seven thousand, seven hundred fifty".