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81317470 = 25131036073
BaseRepresentation
bin1001101100011…
…00111001011110
312200000100121011
410312030321132
5131304124340
612022525434
72005121113
oct466147136
9180010534
1081317470
11419a1023
122329687a
1313b01c60
14ab2a90a
1572140ea
hex4d8ce5e

81317470 has 32 divisors (see below), whose sum is σ = 159187392. Its totient is φ = 29728512.

The previous prime is 81317461. The next prime is 81317491. The reversal of 81317470 is 7471318.

It is a super-2 number, since 2×813174702 = 13225061854401800, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10354 + ... + 16426.

It is an arithmetic number, because the mean of its divisors is an integer number (4974606).

Almost surely, 281317470 is an apocalyptic number.

81317470 is a deficient number, since it is larger than the sum of its proper divisors (77869922).

81317470 is a wasteful number, since it uses less digits than its factorization.

81317470 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6196.

The product of its (nonzero) digits is 4704, while the sum is 31.

The square root of 81317470 is about 9017.6199742504. The cubic root of 81317470 is about 433.2394069931.

Adding to 81317470 its reverse (7471318), we get a palindrome (88788788).

The spelling of 81317470 in words is "eighty-one million, three hundred seventeen thousand, four hundred seventy".

Divisors: 1 2 5 10 13 26 65 103 130 206 515 1030 1339 2678 6073 6695 12146 13390 30365 60730 78949 157898 394745 625519 789490 1251038 3127595 6255190 8131747 16263494 40658735 81317470