81538635 has 8 divisors (see below), whose sum is σ = 130461840. Its totient is φ = 43487264.

The previous prime is 81538609. The next prime is 81538637. The reversal of 81538635 is 53683518.

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 81538635 - 2⁹ = 81538123 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81538593 and 81538602.

It is not an unprimeable number, because it can be changed into a prime (81538637) 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, 2717940 + ... + 2717969.

It is an arithmetic number, because the mean of its divisors is an integer number (16307730).

Almost surely, 2^81538635 is an apocalyptic number.

81538635 is a deficient number, since it is larger than the sum of its proper divisors (48923205).

81538635 is a wasteful number, since it uses less digits than its factorization.

81538635 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5435917.

The product of its digits is 86400, while the sum is 39.

The square root of 81538635 is about 9029.8745838467. The cubic root of 81538635 is about 433.6318222896.

The spelling of 81538635 in words is "eighty-one million, five hundred thirty-eight thousand, six hundred thirty-five".