81357645 has 8 divisors (see below), whose sum is σ = 130172256. Its totient is φ = 43390736.

The previous prime is 81357623. The next prime is 81357781. The reversal of 81357645 is 54675318.

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 81357645 - 2⁸ = 81357389 is a prime.

It is a super-3 number, since 3×81357645³ (a number of 25 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2711907 + ... + 2711936.

It is an arithmetic number, because the mean of its divisors is an integer number (16271532).

Almost surely, 2^81357645 is an apocalyptic number.

It is an amenable number.

81357645 is a deficient number, since it is larger than the sum of its proper divisors (48814611).

81357645 is a wasteful number, since it uses less digits than its factorization.

81357645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5423851.

The product of its digits is 100800, while the sum is 39.

The square root of 81357645 is about 9019.8472825209. The cubic root of 81357645 is about 433.3107427408.

The spelling of 81357645 in words is "eighty-one million, three hundred fifty-seven thousand, six hundred forty-five".