81553875 has 32 divisors (see below), whose sum is σ = 146153280. Its totient is φ = 40147200.

The previous prime is 81553873. The next prime is 81553877. The reversal of 81553875 is 57835518.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (81553873) and next prime (81553877).

It is not a de Polignac number, because 81553875 - 2¹ = 81553873 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81553873) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3490 + ... + 13239.

It is an arithmetic number, because the mean of its divisors is an integer number (4567290).

Almost surely, 2^81553875 is an apocalyptic number.

81553875 is a deficient number, since it is larger than the sum of its proper divisors (64599405).

81553875 is a wasteful number, since it uses less digits than its factorization.

81553875 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16760 (or 16750 counting only the distinct ones).

The product of its digits is 168000, while the sum is 42.

The square root of 81553875 is about 9030.7184099605. The cubic root of 81553875 is about 433.6588366298.

It can be divided in two parts, 81553 and 875, that added together give a palindrome (82428).

The spelling of 81553875 in words is "eighty-one million, five hundred fifty-three thousand, eight hundred seventy-five".