81630252 has 72 divisors (see below), whose sum is σ = 226873920. Its totient is φ = 24541920.

The previous prime is 81630247. The next prime is 81630257. The reversal of 81630252 is 25203618.

81630252 is a `hidden beast` number, since 8 + 1 + 630 + 25 + 2 = 666.

It is an interprime number because it is at equal distance from previous prime (81630247) and next prime (81630257).

It is not an unprimeable number, because it can be changed into a prime (81630257) 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 23 ways as a sum of consecutive naturals, for example, 54303 + ... + 55785.

Almost surely, 2^81630252 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 81630252, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (113436960).

81630252 is an abundant number, since it is smaller than the sum of its proper divisors (145243668).

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

81630252 is a wasteful number, since it uses less digits than its factorization.

81630252 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1643 (or 1638 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

The square root of 81630252 is about 9034.9461536857. The cubic root of 81630252 is about 433.7941714076.

The spelling of 81630252 in words is "eighty-one million, six hundred thirty thousand, two hundred fifty-two".