81413680 has 40 divisors (see below), whose sum is σ = 200424672. Its totient is φ = 30649344.

The previous prime is 81413639. The next prime is 81413681. The reversal of 81413680 is 8631418.

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×81413680² = 13256374582284800, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81413681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28572 + ... + 31291.

Almost surely, 2^81413680 is an apocalyptic number.

81413680 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81413680 is an abundant number, since it is smaller than the sum of its proper divisors (119010992).

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

81413680 is a wasteful number, since it uses less digits than its factorization.

81413680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59893 (or 59887 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 31.

The square root of 81413680 is about 9022.9529534405. The cubic root of 81413680 is about 433.4102006967.

The spelling of 81413680 in words is "eighty-one million, four hundred thirteen thousand, six hundred eighty".