81419520 has 288 divisors, whose sum is σ = 321414912. Its totient is φ = 17104896.

The previous prime is 81419519. The next prime is 81419521. The reversal of 81419520 is 2591418.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (81419519) and next prime (81419521).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81419521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 349324 + ... + 349556.

It is an arithmetic number, because the mean of its divisors is an integer number (1116024).

Almost surely, 2^81419520 is an apocalyptic number.

81419520 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 81419520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (160707456).

81419520 is an abundant number, since it is smaller than the sum of its proper divisors (239995392).

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

81419520 is a wasteful number, since it uses less digits than its factorization.

81419520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 277 (or 263 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 30.

The square root of 81419520 is about 9023.2765667467. The cubic root of 81419520 is about 433.4205636359.

The spelling of 81419520 in words is "eighty-one million, four hundred nineteen thousand, five hundred twenty".