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781397 is a prime number
BaseRepresentation
bin10111110110001010101
31110200212122
42332301111
5200001042
624425325
76433061
oct2766125
91420778
10781397
11494091
12318245
13214886
14164aa1
151067d2
hexbec55

781397 has 2 divisors, whose sum is σ = 781398. Its totient is φ = 781396.

The previous prime is 781387. The next prime is 781399. The reversal of 781397 is 793187.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 461041 + 320356 = 679^2 + 566^2 .

It is an emirp because it is prime and its reverse (793187) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2k-781397 is a prime.

It is a super-2 number, since 2×7813972 = 1221162543218, which contains 22 as substring.

Together with 781399, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 781397.

It is not a weakly prime, because it can be changed into another prime (781399) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 390698 + 390699.

It is an arithmetic number, because the mean of its divisors is an integer number (390699).

2781397 is an apocalyptic number.

781397 is the 473-rd centered heptagonal number.

It is an amenable number.

781397 is a deficient number, since it is larger than the sum of its proper divisors (1).

781397 is an equidigital number, since it uses as much as digits as its factorization.

781397 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10584, while the sum is 35.

The square root of 781397 is about 883.9666283294. The cubic root of 781397 is about 92.1065636651.

The spelling of 781397 in words is "seven hundred eighty-one thousand, three hundred ninety-seven".