81782613 has 12 divisors (see below), whose sum is σ = 128869728. Its totient is φ = 49565160.

The previous prime is 81782611. The next prime is 81782621. The reversal of 81782613 is 31628718.

It is not a de Polignac number, because 81782613 - 2¹ = 81782611 is a prime.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81782611) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 412945 + ... + 413142.

It is an arithmetic number, because the mean of its divisors is an integer number (10739144).

Almost surely, 2^81782613 is an apocalyptic number.

It is an amenable number.

81782613 is a deficient number, since it is larger than the sum of its proper divisors (47087115).

81782613 is a wasteful number, since it uses less digits than its factorization.

81782613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 826104 (or 826101 counting only the distinct ones).

The product of its digits is 16128, while the sum is 36.

The square root of 81782613 is about 9043.3739831990. The cubic root of 81782613 is about 434.0638926370.

The spelling of 81782613 in words is "eighty-one million, seven hundred eighty-two thousand, six hundred thirteen".