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1991313 = 32972281
BaseRepresentation
bin111100110001010010001
310202011120100
413212022101
51002210223
6110403013
722632402
oct7461221
93664510
101991313
111140115
12800469
135494bc
1439b9a9
15295043
hex1e6291

1991313 has 12 divisors (see below), whose sum is σ = 2907268. Its totient is φ = 1313280.

The previous prime is 1991293. The next prime is 1991351. The reversal of 1991313 is 3131991.

It can be written as a sum of positive squares in 2 ways, for example, as 1046529 + 944784 = 1023^2 + 972^2 .

It is not a de Polignac number, because 1991313 - 25 = 1991281 is a prime.

It is a nude number because it is divisible by every one of its digits.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1991413) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 268 + ... + 2013.

21991313 is an apocalyptic number.

It is an amenable number.

1991313 is a deficient number, since it is larger than the sum of its proper divisors (915955).

1991313 is a wasteful number, since it uses less digits than its factorization.

1991313 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2384 (or 2381 counting only the distinct ones).

The product of its digits is 729, while the sum is 27.

The square root of 1991313 is about 1411.1389017386. The cubic root of 1991313 is about 125.8094246736.

It can be divided in two parts, 1991 and 313, that added together give a square (2304 = 482).

The spelling of 1991313 in words is "one million, nine hundred ninety-one thousand, three hundred thirteen".

Divisors: 1 3 9 97 291 873 2281 6843 20529 221257 663771 1991313