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1660991 = 23257281
BaseRepresentation
bin110010101100000111111
310010101110012
412111200333
5411122431
655333435
720055353
oct6254077
93111405
101660991
11a34a22
1268127b
13462047
14313463
1522c22b
hex19583f

1660991 has 8 divisors (see below), whose sum is σ = 1746144. Its totient is φ = 1576960.

The previous prime is 1660963. The next prime is 1661003. The reversal of 1660991 is 1990661.

It is a happy number.

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 1660991 - 214 = 1644607 is a prime.

It is a super-2 number, since 2×16609912 = 5517782204162, which contains 22 as substring.

1660991 is a strobogrammatic number because it is the same when read upside-down.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1660921) 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, 5771 + ... + 6051.

It is an arithmetic number, because the mean of its divisors is an integer number (218268).

21660991 is an apocalyptic number.

1660991 is a deficient number, since it is larger than the sum of its proper divisors (85153).

1660991 is a wasteful number, since it uses less digits than its factorization.

1660991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 561.

The product of its (nonzero) digits is 2916, while the sum is 32.

The square root of 1660991 is about 1288.7943978773. The cubic root of 1660991 is about 118.4283721497.

The spelling of 1660991 in words is "one million, six hundred sixty thousand, nine hundred ninety-one".

Divisors: 1 23 257 281 5911 6463 72217 1660991