81369750 has 128 divisors (see below), whose sum is σ = 253393920. Its totient is φ = 16896000.

The previous prime is 81369749. The next prime is 81369751. The reversal of 81369750 is 5796318.

It is an interprime number because it is at equal distance from previous prime (81369749) and next prime (81369751).

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 81369699 and 81369708.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81369751) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 57046 + ... + 58454.

It is an arithmetic number, because the mean of its divisors is an integer number (1979640).

Almost surely, 2^81369750 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81369750, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (126696960).

81369750 is an abundant number, since it is smaller than the sum of its proper divisors (172024170).

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

81369750 is a wasteful number, since it uses less digits than its factorization.

81369750 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1447 (or 1437 counting only the distinct ones).

The product of its (nonzero) digits is 45360, while the sum is 39.

The square root of 81369750 is about 9020.5182777931. The cubic root of 81369750 is about 433.3322320814.

The spelling of 81369750 in words is "eighty-one million, three hundred sixty-nine thousand, seven hundred fifty".