81669120 has 176 divisors, whose sum is σ = 281994720. Its totient is φ = 20054016.

The previous prime is 81669109. The next prime is 81669121. The reversal of 81669120 is 2196618.

It is not an unprimeable number, because it can be changed into a prime (81669121) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 199476 + ... + 199884.

Almost surely, 2^81669120 is an apocalyptic number.

81669120 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 81669120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (140997360).

81669120 is an abundant number, since it is smaller than the sum of its proper divisors (200325600).

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

81669120 is a wasteful number, since it uses less digits than its factorization.

81669120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 450 (or 432 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 33.

The square root of 81669120 is about 9037.0968789761. The cubic root of 81669120 is about 433.8630104148.

The spelling of 81669120 in words is "eighty-one million, six hundred sixty-nine thousand, one hundred twenty".