81432481 has 6 divisors (see below), whose sum is σ = 88178550. Its totient is φ = 75168288.

The previous prime is 81432473. The next prime is 81432503. The reversal of 81432481 is 18423418.

81432481 = T₃₅₃₃ + T₃₅₃₄ + ... + T₃₅₄₅.

It can be written as a sum of positive squares in 3 ways, for example, as 8910225 + 72522256 = 2985^2 + 8516^2 .

It is not a de Polignac number, because 81432481 - 2³ = 81432473 is a prime.

It is a super-2 number, since 2×81432481² = 13262497923630722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81432451) 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, 240756 + ... + 241093.

It is an arithmetic number, because the mean of its divisors is an integer number (14696425).

Almost surely, 2^81432481 is an apocalyptic number.

It is an amenable number.

81432481 is a deficient number, since it is larger than the sum of its proper divisors (6746069).

81432481 is a wasteful number, since it uses less digits than its factorization.

81432481 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 481875 (or 481862 counting only the distinct ones).

The product of its digits is 6144, while the sum is 31.

The square root of 81432481 is about 9023.9947362573. The cubic root of 81432481 is about 433.4435608478.

Adding to 81432481 its reverse (18423418), we get a palindrome (99855899).

The spelling of 81432481 in words is "eighty-one million, four hundred thirty-two thousand, four hundred eighty-one".