81622560 has 48 divisors (see below), whose sum is σ = 257112576. Its totient is φ = 21765888.

The previous prime is 81622553. The next prime is 81622571. The reversal of 81622560 is 6522618.

It is a tau number, because it is divible by the number of its divisors (48).

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

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, 84544 + ... + 85503.

It is an arithmetic number, because the mean of its divisors is an integer number (5356512).

Almost surely, 2^81622560 is an apocalyptic number.

81622560 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81622560 is an abundant number, since it is smaller than the sum of its proper divisors (175490016).

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

81622560 is a wasteful number, since it uses less digits than its factorization.

81622560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 170065 (or 170057 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 30.

The square root of 81622560 is about 9034.5204632011. The cubic root of 81622560 is about 433.7805455377.

The spelling of 81622560 in words is "eighty-one million, six hundred twenty-two thousand, five hundred sixty".