81453820 has 48 divisors (see below), whose sum is σ = 199664640. Its totient is φ = 27330624.

The previous prime is 81453809. The next prime is 81453859. The reversal of 81453820 is 2835418.

81453820 is digitally balanced in base 9, because in such base it contains all the possibile digits an equal number of times.

81453820 is strictly pandigital in base 9.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 391 + ... + 12769.

It is an arithmetic number, because the mean of its divisors is an integer number (4159680).

Almost surely, 2^81453820 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81453820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (99832320).

81453820 is an abundant number, since it is smaller than the sum of its proper divisors (118210820).

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

81453820 is a wasteful number, since it uses less digits than its factorization.

81453820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12442 (or 12440 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 31.

The square root of 81453820 is about 9025.1770065744. The cubic root of 81453820 is about 433.4814181591.

It can be divided in two parts, 814 and 53820, that multiplied together give a triangular number (43809480 = T₉₃₆₀).

The spelling of 81453820 in words is "eighty-one million, four hundred fifty-three thousand, eight hundred twenty".