81350013 has 16 divisors (see below), whose sum is σ = 112820480. Its totient is φ = 52094016.

The previous prime is 81349991. The next prime is 81350033. The reversal of 81350013 is 31005318.

It is a happy number.

It is not a de Polignac number, because 81350013 - 2²⁴ = 64572797 is a prime.

It is a super-3 number, since 3×81350013³ (a number of 25 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81350033) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4131 + ... + 13407.

It is an arithmetic number, because the mean of its divisors is an integer number (7051280).

Almost surely, 2^81350013 is an apocalyptic number.

It is an amenable number.

81350013 is a deficient number, since it is larger than the sum of its proper divisors (31470467).

81350013 is a wasteful number, since it uses less digits than its factorization.

81350013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9396.

The product of its (nonzero) digits is 360, while the sum is 21.

The square root of 81350013 is about 9019.4242055688. The cubic root of 81350013 is about 433.2971929754.

The spelling of 81350013 in words is "eighty-one million, three hundred fifty thousand, thirteen".