81456620 has 72 divisors (see below), whose sum is σ = 203719824. Its totient is φ = 27264384.

The previous prime is 81456619. The next prime is 81456631. The reversal of 81456620 is 2665418.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 41174 + ... + 43106.

It is an arithmetic number, because the mean of its divisors is an integer number (2829442).

Almost surely, 2^81456620 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 81456620, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (101859912).

81456620 is an abundant number, since it is smaller than the sum of its proper divisors (122263204).

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

81456620 is a wasteful number, since it uses less digits than its factorization.

81456620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1999 (or 1990 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 32.

The square root of 81456620 is about 9025.3321268527. The cubic root of 81456620 is about 433.4863851210.

The spelling of 81456620 in words is "eighty-one million, four hundred fifty-six thousand, six hundred twenty".