81761357 has 8 divisors (see below), whose sum is σ = 82565784. Its totient is φ = 80961088.

The previous prime is 81761269. The next prime is 81761369. The reversal of 81761357 is 75316718.

It can be written as a sum of positive squares in 4 ways, for example, as 55741156 + 26020201 = 7466^2 + 5101^2 .

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 81761357 - 2⁸ = 81761101 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 81761357.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81761377) 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, 49883 + ... + 51495.

It is an arithmetic number, because the mean of its divisors is an integer number (10320723).

Almost surely, 2^81761357 is an apocalyptic number.

It is an amenable number.

81761357 is a deficient number, since it is larger than the sum of its proper divisors (804427).

81761357 is a wasteful number, since it uses less digits than its factorization.

81761357 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2079.

The product of its digits is 35280, while the sum is 38.

The square root of 81761357 is about 9042.1986817366. The cubic root of 81761357 is about 434.0262837402.

The spelling of 81761357 in words is "eighty-one million, seven hundred sixty-one thousand, three hundred fifty-seven".