81406732608 has 42 divisors (see below), whose sum is σ = 233337702234. Its totient is φ = 27135577344.

The previous prime is 81406732607. The next prime is 81406732609. The reversal of 81406732608 is 80623760418.

81406732608 is a `hidden beast` number, since 8 + 1 + 4 + 0 + 6 + 7 + 32 + 608 = 666.

It is an interprime number because it is at equal distance from previous prime (81406732607) and next prime (81406732609).

It can be written as a sum of positive squares in only one way, i.e., 50862878784 + 30543853824 = 225528^2 + 174768^2 .

It is a super-2 number, since 2×81406732608² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81406732607) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 70664991 + ... + 70666142.

It is an arithmetic number, because the mean of its divisors is an integer number (5555659577).

Almost surely, 2^81406732608 is an apocalyptic number.

It is an amenable number.

81406732608 is an abundant number, since it is smaller than the sum of its proper divisors (151930969626).

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

81406732608 is a wasteful number, since it uses less digits than its factorization.

81406732608 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 141331151 (or 141331138 counting only the distinct ones).

The product of its (nonzero) digits is 387072, while the sum is 45.

The spelling of 81406732608 in words is "eighty-one billion, four hundred six million, seven hundred thirty-two thousand, six hundred eight".