81651456 has 72 divisors (see below), whose sum is σ = 241478160. Its totient is φ = 27214848.

The previous prime is 81651433. The next prime is 81651467. The reversal of 81651456 is 65415618.

It is a tau number, because it is divible by the number of its divisors (72).

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

It is a self number, because there is not a number n which added to its sum of digits gives 81651456.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1006 + ... + 12818.

Almost surely, 2^81651456 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 81651456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (120739080).

81651456 is an abundant number, since it is smaller than the sum of its proper divisors (159826704).

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

81651456 is a wasteful number, since it uses less digits than its factorization.

81651456 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11838 (or 11818 counting only the distinct ones).

The product of its digits is 28800, while the sum is 36.

The square root of 81651456 is about 9036.1195211219. The cubic root of 81651456 is about 433.8317284614.

The spelling of 81651456 in words is "eighty-one million, six hundred fifty-one thousand, four hundred fifty-six".