81669600 has 288 divisors, whose sum is σ = 312480000. Its totient is φ = 20528640.

The previous prime is 81669557. The next prime is 81669607. The reversal of 81669600 is 696618.

It is a tau number, because it is divible by the number of its divisors (288).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81669607) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 410301 + ... + 410499.

It is an arithmetic number, because the mean of its divisors is an integer number (1085000).

Almost surely, 2^81669600 is an apocalyptic number.

81669600 is a gapful number since it is divisible by the number (80) 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 81669600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (156240000).

81669600 is an abundant number, since it is smaller than the sum of its proper divisors (230810400).

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

81669600 is a wasteful number, since it uses less digits than its factorization.

81669600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 247 (or 228 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 36.

The square root of 81669600 is about 9037.1234361383. The cubic root of 81669600 is about 433.8638604049.

It can be divided in two parts, 8166 and 9600, that added together give a triangular number (17766 = T₁₈₈).

The spelling of 81669600 in words is "eighty-one million, six hundred sixty-nine thousand, six hundred".