81494641 has 4 divisors (see below), whose sum is σ = 81728500. Its totient is φ = 81260784.

The previous prime is 81494603. The next prime is 81494653. The reversal of 81494641 is 14649418.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 22127616 + 59367025 = 4704^2 + 7705^2 .

It is a cyclic number.

It is not a de Polignac number, because 81494641 - 2²¹ = 79397489 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81494641.

It is not an unprimeable number, because it can be changed into a prime (81494671) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 116406 + ... + 117103.

It is an arithmetic number, because the mean of its divisors is an integer number (20432125).

Almost surely, 2^81494641 is an apocalyptic number.

It is an amenable number.

81494641 is a deficient number, since it is larger than the sum of its proper divisors (233859).

81494641 is a wasteful number, since it uses less digits than its factorization.

81494641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 233858.

The product of its digits is 27648, while the sum is 37.

The square root of 81494641 is about 9027.4382301958. The cubic root of 81494641 is about 433.5538198782.

The spelling of 81494641 in words is "eighty-one million, four hundred ninety-four thousand, six hundred forty-one".