81450684 has 72 divisors (see below), whose sum is σ = 244037248. Its totient is φ = 23269680.

The previous prime is 81450683. The next prime is 81450697. The reversal of 81450684 is 48605418.

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 (81450683) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 819 + ... + 12789.

Almost surely, 2^81450684 is an apocalyptic number.

81450684 is a gapful number since it is divisible by the number (84) 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 81450684, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (122018624).

81450684 is an abundant number, since it is smaller than the sum of its proper divisors (162586564).

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

81450684 is a wasteful number, since it uses less digits than its factorization.

81450684 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11997 (or 11983 counting only the distinct ones).

The product of its (nonzero) digits is 30720, while the sum is 36.

The square root of 81450684 is about 9025.0032686975. The cubic root of 81450684 is about 433.4758550267.

The spelling of 81450684 in words is "eighty-one million, four hundred fifty thousand, six hundred eighty-four".