81472286440 has 24 divisors (see below), whose sum is σ = 183316706370. Its totient is φ = 32588192480.

The previous prime is 81472286411. The next prime is 81472286443. The reversal of 81472286440 is 4468227418.

It can be written as a sum of positive squares in only one way, i.e., 73325057796 + 8147228644 = 270786^2 + 90262^2 .

It is a super-2 number, since 2×81472286440² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81472286443) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1782675 + ... + 1827805.

Almost surely, 2^81472286440 is an apocalyptic number.

It is an amenable number.

81472286440 is an abundant number, since it is smaller than the sum of its proper divisors (101844419930).

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

81472286440 is an frugal number, since it uses more digits than its factorization.

81472286440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90273 (or 45138 counting only the distinct ones).

The product of its (nonzero) digits is 688128, while the sum is 46.

The spelling of 81472286440 in words is "eighty-one billion, four hundred seventy-two million, two hundred eighty-six thousand, four hundred forty".