81148013 has 4 divisors (see below), whose sum is σ = 81179328. Its totient is φ = 81116700.

The previous prime is 81147973. The next prime is 81148019. The reversal of 81148013 is 31084118.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81148013 - 2⁶ = 81147949 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81148019) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11381 + ... + 17082.

It is an arithmetic number, because the mean of its divisors is an integer number (20294832).

Almost surely, 2^81148013 is an apocalyptic number.

It is an amenable number.

81148013 is a deficient number, since it is larger than the sum of its proper divisors (31315).

81148013 is a wasteful number, since it uses less digits than its factorization.

81148013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31314.

The product of its (nonzero) digits is 768, while the sum is 26.

The square root of 81148013 is about 9008.2191913829. The cubic root of 81148013 is about 432.9382560186.

The spelling of 81148013 in words is "eighty-one million, one hundred forty-eight thousand, thirteen".