81261313 has 8 divisors (see below), whose sum is σ = 93270528. Its totient is φ = 69352224.

The previous prime is 81261311. The next prime is 81261329. The reversal of 81261313 is 31316218.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81261313 - 2¹ = 81261311 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81261311) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23281 + ... + 26542.

It is an arithmetic number, because the mean of its divisors is an integer number (11658816).

Almost surely, 2^81261313 is an apocalyptic number.

It is an amenable number.

81261313 is a deficient number, since it is larger than the sum of its proper divisors (12009215).

81261313 is a wasteful number, since it uses less digits than its factorization.

81261313 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50063.

The product of its digits is 864, while the sum is 25.

The square root of 81261313 is about 9014.5056991496. The cubic root of 81261313 is about 433.1396538155.

The spelling of 81261313 in words is "eighty-one million, two hundred sixty-one thousand, three hundred thirteen".