81629061264 has 135 divisors (see below), whose sum is σ = 236885686219. Its totient is φ = 26239422720.

The previous prime is 81629061247. The next prime is 81629061271. The reversal of 81629061264 is 46216092618.

The square root of 81629061264 is 285708.

It is a perfect power (a square), and thus also a powerful number.

81629061264 is a `hidden beast` number, since 8 + 1 + 6 + 29 + 0 + 612 + 6 + 4 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 3587051664 + 78042009600 = 59892^2 + 279360^2 .

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 99425974 + ... + 99426794.

Almost surely, 2^81629061264 is an apocalyptic number.

81629061264 is the 285708-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81629061264

81629061264 is an abundant number, since it is smaller than the sum of its proper divisors (155256624955).

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

81629061264 is an equidigital number, since it uses as much as digits as its factorization.

81629061264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1714 (or 855 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 45.

The spelling of 81629061264 in words is "eighty-one billion, six hundred twenty-nine million, sixty-one thousand, two hundred sixty-four".