81622520 has 32 divisors (see below), whose sum is σ = 209887200. Its totient is φ = 27984768.

The previous prime is 81622517. The next prime is 81622531. The reversal of 81622520 is 2522618.

It is a self number, because there is not a number n which added to its sum of digits gives 81622520.

It is a congruent number.

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 7 ways as a sum of consecutive naturals, for example, 145475 + ... + 146034.

It is an arithmetic number, because the mean of its divisors is an integer number (6558975).

Almost surely, 2^81622520 is an apocalyptic number.

It is an amenable number.

81622520 is an abundant number, since it is smaller than the sum of its proper divisors (128264680).

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

81622520 is a wasteful number, since it uses less digits than its factorization.

81622520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 291527 (or 291523 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 26.

The square root of 81622520 is about 9034.5182494696. The cubic root of 81622520 is about 433.7804746781.

The spelling of 81622520 in words is "eighty-one million, six hundred twenty-two thousand, five hundred twenty".