81530253 has 16 divisors (see below), whose sum is σ = 138040960. Its totient is φ = 46588608.

The previous prime is 81530243. The next prime is 81530287. The reversal of 81530253 is 35203518.

81530253 is a `hidden beast` number, since 81 + 530 + 2 + 53 = 666.

It is not a de Polignac number, because 81530253 - 2²⁰ = 80481677 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81530213) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 215500 + ... + 215877.

It is an arithmetic number, because the mean of its divisors is an integer number (8627560).

Almost surely, 2^81530253 is an apocalyptic number.

It is an amenable number.

81530253 is a deficient number, since it is larger than the sum of its proper divisors (56510707).

81530253 is a wasteful number, since it uses less digits than its factorization.

81530253 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 431393 (or 431387 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 27.

The square root of 81530253 is about 9029.4104458708. The cubic root of 81530253 is about 433.6169629676.

The spelling of 81530253 in words is "eighty-one million, five hundred thirty thousand, two hundred fifty-three".